Course Content
GATE Architecture & Planning (AR) — Preparation Course

LESSON 5.6 — Housing: Concepts, Typologies and Slums


A. Standard Map — Lesson 5.6

Topic Governing Source Exam Focus
House vs housing WHO adequate housing; NBC 2016 Part 3; URDPFI 2015 Housing = system (dwellings + services + community); House = single structure
Tenure types Transfer of Property Act 1882; State Rent Control Acts Freehold / leasehold / rental / cooperative — definitions and implications
Built-form typology NBC 2016; URDPFI standards Row / semi-detached / detached / flat / walk-up / high-rise — density implications
Slum definitions Census 2011 (3 categories); NSSO 69th Round; Slum Areas Act 1956; PMAY-U Not interchangeable — each has different threshold and legal implication
Slum morphology UN-Habitat (2006); ch09-part01 Four axes: tenure security, service access, density/overcrowding, physical quality
Intervention approaches ch09-part01; ch01-part03 In-situ upgrading vs relocation vs redevelopment — when each is appropriate
Housing needs vs demand Deepak Parekh Committee 2008; TG-12 Effective demand = willingness + ability to pay; latent = need without purchasing power

Exam Anchor: The three slum definitions (Census, Slum Areas Act, PMAY-U) use different thresholds and have different legal implications. A question asking which definition applies to a given scenario requires identifying the governing authority, not just the physical description.

Source: ch09-part01; NBC 2016 Part 3; Census of India 2011; PMAY-U Mission Guidelines 2015.


B. Mechanism in Words — Housing System

  1. Individual shelter need arises — a household requires protection from weather, security, and a base for social and economic life.
  2. Tenure mechanism determines legal status — how the household holds rights over the land and structure: ownership (freehold/leasehold), rental, or cooperative share.
  3. Delivery channel shapes the built form — government, private developer, self-build, or cooperative society determines typology (row housing, walk-up flat, high-rise), plot size, and quality.
  4. Service access completes the housing system — water supply, sanitation, drainage, roads, and solid waste management transform a structure into a dwelling.
  5. Settlement quality emerges — the combination of tenure security, built form, service access, and density determines whether a settlement qualifies as formal housing, informal settlement, or slum.
  6. Policy intervention path is selected based on settlement condition — in-situ upgrading (services improved), in-situ redevelopment (fabric rebuilt on same land), or relocation (residents moved to new site).

C. Core Concept Explanations — Lesson 5.6

C1. House vs Housing — The System Distinction

The distinction between a house and housing is the foundation of all urban housing analysis.

House Housing
Definition A single physical structure providing shelter A system of dwellings, services, open spaces, and social relationships constituting a living environment
Scope One dwelling unit An aggregation of units + infrastructure + community
Measure Number of rooms; floor area; structural type Density; service coverage; tenure security; affordability ratio
Policy implication Construction of a unit Provision of a complete residential environment
Indian example A DDA flat unit Tughlaqabad Extension EWS colony — flats + roads + water + community facilities

Source: WHO Adequate Housing definition; ch09-part01 Section 9.1; NBC 2016 Part 3 preamble.

The WHO identifies adequate housing as requiring: (a) security of tenure, (b) availability of services, (c) affordability, (d) habitability, (e) accessibility, (f) location, and (g) cultural adequacy. All seven are system-level attributes, not unit-level attributes.

Housing shortage components (TG-12 Technical Group on Urban Housing Shortage, 2012):
Congestion: Households sharing a unit with another household
Obsolescence: Kutcha/semi-pucca structures requiring replacement
Homelessness: Households with no shelter
New household formation: Future demand from population growth and declining household size

TG-12 finding: Total urban housing shortage = 18.78 million units (at that time); 95.6% in EWS and LIG categories. This data is exam-frequently cited.


C2. Tenure — Freehold, Leasehold, Rental, Cooperative

Tenure determines legal rights, investment incentives, and access to credit. The Transfer of Property Act 1882 (Sections 105–117) and State Rent Control Acts govern tenure relationships.

Tenure Type Core Character Legal Basis Security Level Indian Context
Freehold Owner holds land and structure in perpetuity; full rights to sell, mortgage, or bequeath; no ground rent payable Transfer of Property Act 1882; Registration Act 1908 Highest — absolute ownership Most preferred for mortgage lending; DDA sold freehold plots in early phases; most private developer apartments now freehold
Leasehold Right to use property for a defined term (30/60/99 years) granted by lessor; lessee pays ground rent; property reverts to lessor at term end Transfer of Property Act 1882, Sections 105–117; development authority allotment letters Medium — time-bound right with conditions DDA and MMRDA commonly allot on 99-year leasehold; most government land is leasehold; creates complications for resale and mortgage
Rental Right to occupy for a shorter, renewable period in exchange for monthly rent; governed by state Rent Control Acts Maharashtra Rent Control Act (11-month leave and license), Delhi Rent Control Act 1958 Lower — tenant rights restricted by Act provisions India has a large informal rental market; Model Tenancy Act 2021 seeks to balance landlord-tenant interests and encourage institutional rental investment
Cooperative A registered cooperative society holds land and building in trust for members; members hold shares proportionate to their unit and enjoy an occupancy right State Cooperative Societies Acts; bye-laws of the society Medium-high — secure occupancy within society governance Common in Mumbai, Chennai, Delhi; RERA 2016 mandates formation of owners’ associations for projects with more than one unit
Group Housing Multiple owners share common land and services through a Residents’ Welfare Association (RWA) RERA 2016 (mandatory RWA for multi-unit projects); local Apartment Ownership Acts High — individual ownership of unit + shared ownership of common areas Dominant form in new apartment complexes; RERA escrow protects buyers

Leasehold vs freehold — exam trap:
– DDA flats are typically leasehold (99-year), not freehold. After the lease period, the land reverts to DDA (in theory) unless renewed.
– When a GATE question asks “most secure tenure” → freehold. When asked about “most common government housing authority tenure” → leasehold.

Source: Transfer of Property Act 1882; ch09-part01 Section 9.2.1; ch09-part03 Section 9.12.


C3. Housing Typology — Built Form Classification

Housing typology describes the physical organisation of dwelling units in relation to each other and to the land.

Typology Description Density Indian Application
Detached (Bungalow) Single dwelling on its own plot; no shared walls Lowest — highest land consumption per unit HIG individual houses; independent villas; colonial bungalows
Semi-detached Two dwellings sharing one common wall; each on its own half-plot Low Common in LIG/MIG plotted layouts in smaller towns
Row housing / Terraced Multiple dwellings in a continuous row, sharing side walls; front and rear gardens Low-medium EWS/LIG plotted schemes; URDPFI recommends for LIG
Walk-up apartment (G+3/G+4) Multi-storey building up to 4 floors without a lift; each floor has multiple units Medium PMAY-U EWS/LIG apartments; most affordable apartment type; no lift cost
Low-rise flat (G+5 to G+7) Multi-storey with lift; moderate height Medium-high MIG/LIG apartments; common in planned housing colonies
High-rise apartment 15m+ height (NBC 2016 trigger); typically above 7 floors High MIG/HIG; PMAY-U ISSR cross-subsidy units; BKC and Powai, Mumbai

NBC 2016 height thresholds:
– High-rise trigger: above 15 metres
– Above 30m or 11 floors: enhanced fire safety requirements

URDPFI minimum plot sizes (exam reference):

Income Group Metro plot (minimum) Non-metro
EWS 25 sq.m up to 40 sq.m
LIG 40–80 sq.m 40–80 sq.m
MIG 80–150 sq.m 80–150 sq.m
HIG 150+ sq.m 150+ sq.m

C4. Slum Definitions — Not Interchangeable

India has three distinct official slum definitions, each from a different authority with different thresholds and legal implications. These are not interchangeable — using the wrong definition in an exam answer about eligibility or legal status changes the answer.

Definition 1 — Census of India 2011 (Statistical identification):

Three categories:

Census Category Operational Definition Threshold Legal Implication
Notified Slum Formally notified by state government/UT/local body under any slum statute None specified separately — formal notification is the criterion Legal protection from eviction; entitled to improvement programmes
Recognized Slum Recognized by state/UT/local body or housing board, even without formal statutory notification May trigger welfare scheme benefits; less legal protection than notified
Identified Slum Compact area with ≥ 300 persons OR 60–70 households in poorly built, congested tenements with inadequate infrastructure, without formal notification 300 persons or 60–70 households Statistical identification only; NO protection from demolition

Census slum population (2011): 65.49 million = 17.4% of urban population across 2,613 cities and towns.

Definition 2 — NSSO 69th Round 2012 (Alternative statistical):

NSSO Category Threshold
Notified Slum Same as Census notified
Non-notified Slum A compact settlement with poorly built tenements, crowded, inadequate sanitation + water, where at least 20 households reside

Key difference: NSSO threshold is 20 households (much smaller than Census identified threshold of 60–70 households). NSSO captures smaller informal settlements the Census may miss.

Definition 3 — PMAY-U / Mission Guidelines (Programme eligibility):

PMAY-U does not provide a standalone statutory slum definition — it uses the state government’s notified slum list or local body identification for ISSR vertical eligibility. The key criterion is formal identification by the state/local body as a slum in need of rehabilitation.

Definition 4 — Slum Areas (Improvement and Clearance) Act, 1956 (Legal / statutory):

Under the Slum Areas Act 1956, a “slum area” is an area notified by the state government as insanitary, overcrowded, and hazardous to public health. Once notified, the government may:
– Carry out improvement works
– Acquire the land for clearance
– Direct that no further construction be permitted

Critical distinction for exams:
– Census Identified = 300 persons / 60–70 HH threshold; statistical only; NO legal protection
– NSSO Non-notified = 20 HH threshold; statistical only
– Slum Areas Act notified = formal state notification; legal protection from demolition


C5. Slum Morphology — Four Axes

Slum quality and character can be analysed along four independent axes. This multi-axis framework is more analytically precise than a simple “slum / not slum” binary and is relevant for selecting the appropriate intervention approach.

Axis Range Planning Significance
Tenure security No claim → squatter → tenant → occupancy right → patta/title Higher tenure security → greater household investment in improvement; lower risk of eviction; access to formal credit
Service access None (open defecation, unserved) → shared facilities → individual connections → full service coverage Service access is the primary health determinant; improved sanitation reduces mortality; piped water reduces daily time burden on women
Density / overcrowding High occupancy (>5 persons/room) → moderate → low Higher density → higher fire risk; higher disease transmission; lower private open space
Physical quality of structure Kutcha (temporary materials) → semi-pucca → pucca (RCC/masonry) Structural quality determines vulnerability to floods, fire, seismic events; kutcha structures require annual repair

UN-Habitat’s 5 slum dimensions (for reference; often tested):
1. Lack of access to improved water
2. Lack of access to improved sanitation
3. Insufficient living area (> 3 persons per room)
4. Non-durable structure (kutcha)
5. Insecure tenure

Source: UN-Habitat (2006). State of the World’s Cities 2006/7; ch09-part01 Section 9.3.


C6. Intervention Approaches

The appropriate intervention depends on the position of a settlement on each morphological axis.

Approach When Appropriate Mechanism Key Advantage Key Risk
In-situ Upgrading Good tenure security; existing physical fabric structurally usable; no risk from natural hazard Improve infrastructure (water, sanitation, drainage, roads) within the existing settlement; no relocation Least disruptive; maintains community networks and livelihood proximity Does not address structural inadequacy; only viable if structures are not beyond repair
In-situ Redevelopment Land value high enough to cross-subsidise; structure quality poor; site not hazardous Demolish and rebuild at higher density; cross-subsidy from market-rate units finances free EWS units; PPP model Higher density allows more units; improved structural quality; uses land value Contentious eligibility (cut-off dates); transit accommodation inadequacy; risk of post-rehabilitation resale
Relocation Hazardous location (floodplain, railway corridor, hill slope) where in-situ is not viable Move residents to a new site on peripheral land with planned infrastructure Safety from hazard; planned service provision Breaks community and livelihood networks; peripheral location increases commute cost; high social cost
Land Titling Relatively stable informal settlement; not on hazardous land; residents have de facto tenure Grant legal ownership of occupied land to slum dwellers Most empowering; residents gain collateral for investment; reduces vulnerability; preserves community Politically challenging (competing claims; illegal occupation history); creates precedent

Evolution of slum policy in India (chronological sequence — exam-tested):
1. Demolition & clearance (1950s–1960s) — Slum Areas Act 1956; demolition without adequate rehabilitation; settlements re-emerged elsewhere.
2. Site-and-services and upgrading (1970s–1980s) — World Bank model; EIUS scheme 1972; basic infrastructure provision; self-help construction.
3. In-situ rehabilitation (1990s–2010s) — NSDP 1997; VAMBAY 2001; JNNURM BSUP 2005; dwelling unit provision.
4. Rights-based and demand-driven (2015–present) — PMAY-U 2015; credit subsidies + BLC grant; ISSR cross-subsidy; recognises slum dwellers as rights-bearing citizens.


C7. Housing Needs vs Demand — Effective vs Latent

Concept Definition Policy Implication
Housing need The gap between the existing housing stock and the minimum standard of shelter all households require — includes both qualitative (improving kutcha to pucca) and quantitative (providing for houseless households) aspects Determines the government’s social obligation; the basis for public housing investment
Effective demand Households with both the willingness to pay and the financial capacity to pay for better housing at market or near-market prices Addressed by RERA-registered developers; CLSS/ISS interest subsidy; AHP schemes
Latent demand Households who need better housing but lack the purchasing power to access it in the market — the “missing middle” and below Requires public subsidy, cross-subsidy, or direct grant (ISSR free units, BLC grant)

Affordability ratio benchmarks (Deepak Parekh Committee 2008):
– EWS: EMI ≤ 20% of monthly income; house price ≤ annual income
– Housing costs above these ratios indicate unaffordability

The supply-demand gap:
India’s urban housing market has a structural disconnect: the bulk of housing need is in the EWS/LIG segment (95.6% of TG-12 shortage) but the bulk of private developer supply targets MIG/HIG. PMAY-U’s demand-side interventions (CLSS/ISS) attempt to bridge this gap by making formal housing financially accessible to lower-income households.


D. Parameter Table — Lesson 5.6

Parameter Value Source
Census identified slum threshold ≥ 300 persons or 60–70 HH Census 2011
NSSO non-notified slum threshold ≥ 20 households NSSO 69th Round 2012
Census slum population (2011) 65.49 million (17.4% of urban) Census 2011
Mumbai slum share ~41% of city population Census 2011
Dharavi area / population ~2.1 sq.km / 700,000–1,000,000 Various estimates
UN-Habitat overcrowding threshold > 3 persons per room UN-Habitat 2006
NBC overcrowding benchmark > 2.5 persons per room UN-Habitat / NBC
NBC habitable room minimum area 9.5 sq.m NBC 2016 Part 3
NBC habitable room minimum height 2.75 m NBC 2016 Part 3
URDPFI EWS minimum plot (metro) 25 sq.m URDPFI 2015
High-rise trigger (NBC 2016) above 15 m NBC 2016 Part 4
TG-12 housing shortage 18.78 million units TG-12 Report 2012
TG-12 EWS/LIG share of shortage 95.6% TG-12 Report 2012

E. Common Confusions — Lesson 5.6

Confusion Clarification
“All three Census slum categories have the same legal status” Only Notified slums have legal protection from demolition. Identified slums have statistical recognition only — no protection.
“NSSO and Census use the same threshold” Census identified threshold = 60–70 HH; NSSO non-notified = 20 HH. NSSO captures smaller settlements.
“PMAY-U defines slums” PMAY-U uses state/local body’s notified/identified slum list — it does not independently define a slum
“Latent demand = zero demand” Latent demand = real need without purchasing power; it exists and is large; it drives public housing policy
“Walk-up = high-rise” Walk-up = G+3/G+4, no lift, below 15m. High-rise = above 15m (NBC 2016). Different regulatory categories.
“Leasehold = more secure than freehold” Freehold is more secure — perpetual ownership. Leasehold is time-bound and reverts to the lessor at term end.
“In-situ upgrading = rebuilding the slum” In-situ upgrading = improving services (water, sanitation, drainage) without demolishing structures. Rebuilding = in-situ redevelopment — a higher-intervention approach.

F. Exam Traps — Lesson 5.6

Trap Incorrect Belief Correct Principle
Census slum threshold The Census 300-person threshold is universal for all categories 300/60–70 HH applies to Identified slums only; Notified and Recognized slums are defined by legal/administrative action, not by a population threshold
NSSO vs Census NSSO threshold is the same as Census NSSO = 20 HH; Census Identified = 60–70 HH. NSSO is a smaller threshold — it captures more settlements.
Slum Areas Act = Census Notified All Census Notified slums are notified under the Slum Areas Act 1956 Not necessarily — states have their own slum notification statutes; Census Notified includes all statutory notifications, not only the 1956 Act
Organic housing = slum Pre-planning settlements (Lal Dora areas, organic pols) are slums Organic housing is NOT informal housing — residents hold legal title. The difference is legal status, not physical appearance.
High-rise = above 5 floors High-rise starts at 5 or 7 floors High-rise trigger = above 15 metres (NBC 2016). Floors vary by floor height; the metric trigger is height, not floor count.
Housing shortage = houses needed Housing shortage = total population ÷ household size − existing stock Housing shortage (TG-12 method) = congestion + obsolescence + homelessness + new formation — a composite, not a simple arithmetic

G. Answer-Writing Cues — Lesson 5.6

MSQ (slum definitions — match definition to authority):

Template: “Census Identified = 300 persons or 60–70 HH; no legal protection. NSSO Non-notified = 20 HH. Slum Areas Act Notified = formal state notification; legal protection. PMAY-U = uses state/local body’s notified/identified list. NOT interchangeable — the threshold and legal implication differ in each case.”

Short answer (house vs housing, 2 marks):

Template: “A house is a single physical structure providing shelter. Housing is a system comprising dwellings, associated services (water, sanitation, roads), open spaces, and social relationships. Policy must address the housing system, not just the construction of units — inadequate services render a well-built structure into a substandard living environment.”

Short answer (intervention approach selection, 3 marks):

Template: “The choice of intervention follows from slum morphology: (1) If tenure is secure and structures are serviceable → in-situ upgrading (least disruption; community preserved). (2) If land value supports cross-subsidy and structures are substandard → in-situ redevelopment (ISSR model; higher density; free EWS unit; PPP). (3) If the site is hazardous (floodplain, railway corridor) → relocation (last resort; high social cost; community disruption).”


H. PYQ Linkage Note — Lesson 5.6

Topic Exam Appearance Pattern
Slum definition thresholds GATE AR; UPSC; State PSC MSQ/MCQ matching definition to authority; Census Identified threshold (300/60–70 HH)
Tenure types GATE AR MCQ: most secure tenure = freehold; DDA housing = leasehold
Walk-up vs high-rise distinction GATE AR MCQ on NBC 2016 high-rise trigger (15m)
Housing need vs effective demand UPSC; State PSC Short answer on why public subsidy is needed for EWS/LIG
Slum intervention approaches GATE AR; UPSC MCQ/MSQ matching approach to scenario (hazard zone = relocation; structurally usable = upgrading)

I. Mini-Check — Lesson 5.6

Q1 (MSQ — slum definitions)
Which of the following statements about India’s official slum classifications are correct? (Select all correct answers.)

(A) The Census of India Identified Slum category requires a minimum of 300 persons or 60–70 households
(B) The NSSO non-notified slum threshold is the same as the Census Identified threshold of 60–70 households
(C) Census Notified slums have legal protection from summary demolition
(D) PMAY-U provides an independent statutory definition of a slum with its own population threshold
(E) Organic housing settlements (Lal Dora areas) are classified as informal/slum settlements

Answer: (A), (C)
– (A) Correct — Census Identified = ≥ 300 persons or 60–70 HH.
– (B) Incorrect — NSSO non-notified threshold = 20 HH, not 60–70 HH.
– (C) Correct — Census Notified = legally notified under a slum statute; eligible for protection from demolition and improvement programmes.
– (D) Incorrect — PMAY-U does not define slums independently; it uses state/local body’s notified/identified slum lists.
– (E) Incorrect — Organic housing (Lal Dora) residents hold legal title; this is NOT informal/slum housing.

Q2 (MCQ — intervention approach)
A slum in Mumbai occupies land along the Mithi river floodplain. Despite poor structural quality, the community has strong social networks and residents have been there for over 20 years. What is the most appropriate intervention approach?

(A) In-situ upgrading — improve services without relocation
(B) In-situ redevelopment — rebuild at higher density on the same land
(C) Land titling — grant legal ownership to current occupants
(D) Relocation — move residents to a safer site away from the floodplain

Answer: (D)
The Mithi river floodplain is a hazardous location — risk of flooding makes in-situ options (A, B) physically unsafe regardless of community attachment. Land titling (C) cannot address the physical hazard. Relocation is the only viable approach when the site itself is unsafe — though it carries high social cost, community disruption, and requires adequate alternative housing.

Q3 (MCQ — tenure security)
Which of the following housing tenure types offers the highest security of ownership and is most preferred by banks for mortgage lending?

(A) Cooperative housing (society holds land in trust)
(B) Leasehold (99-year DDA allotment)
(C) Rental (leave-and-license, 11-month agreement)
(D) Freehold (perpetual ownership)

Answer: (D)
Freehold = perpetual ownership with full rights to sell, mortgage, or bequeath; no ground rent. This is the highest-security tenure and the preferred security for mortgage lending. Leasehold (B) is time-bound and reverts to the lessor. Cooperative (A) involves shared ownership through society shares. Rental (C) provides no ownership right.

Q4 (MCQ — house vs housing)

In urban planning terminology, which statement best distinguishes “a house” from “housing”?

(A) A house refers to the social-economic delivery system; housing refers to a single dwelling unit
(B) A house is a single physical dwelling structure; housing is the system of dwellings, services, open spaces, and social relationships that constitute a living environment
(C) Housing applies only to government-built units; a house applies only to privately built units
(D) There is no meaningful distinction — the terms are fully interchangeable in Indian planning practice

Answer: (B)
House = physical unit. Housing = system encompassing tenure, services, community, and policy delivery. This distinction underpins scheme design (PMAY-U verticals target housing systems, not isolated structures).

Q5 (MSQ — slum intervention logic)

A municipal authority is evaluating intervention options for three settlements. Which pairings of settlement condition and preferred intervention approach are correct? (Select all correct.)

(A) Structurally sound slum on secure tenure with service gaps → in-situ upgrading
(B) Slum on high-value inner-city land with substandard structures and developer interest → in-situ redevelopment (ISSR-type PPP)
(C) Slum on a railway corridor buffer zone with flood risk → in-situ upgrading to preserve community networks
(D) Hazardous site (river floodplain, unstable slope) with unsafe structures → relocation/resettlement
(E) Latent demand among EWS households with own land but no capital → beneficiary-led construction support (BLC-type grant)

Answer: (A), (B), (D)
– (A) Correct — upgrading when fabric is usable and displacement is avoidable.
– (B) Correct — redevelopment when cross-subsidy and density gain can fund replacement units.
– (C) Incorrect — hazardous location overrides community preference; in-situ options are unsafe.
– (D) Correct — relocation when the site itself is the primary risk.
– (E) Incorrect in this MSQ set — BLC is a PMAY-U policy vertical (Lesson 5.7), not a generic slum morphology intervention label; slum-specific logic is upgrading/redevelopment/relocation.