Why in NEWS

A Nature Cities global study found that India has the world’s largest number of slum clusters in flood-prone areas, highlighting growing climate vulnerability and urban risk.

Key Terms / Concepts

Term	Explanation
Slum	Poor, crowded settlement with inadequate infrastructure, sanitation, and housing.
Floodplain	Low-lying area adjacent to rivers prone to seasonal or flash flooding.
Flash Flood	Sudden local flood caused by heavy rainfall or dam failure.
Sponge City	Urban model that uses green infrastructure to absorb and manage rainwater.
IFLOWS-Mumbai / CFLOWS-Chennai	City-specific flood warning systems for risk forecasting.

What the Study Reveals

Key Point	Details
India’s Rank	India has the highest number of slum dwellers in flood-prone zones (158 million+).
Risk Zones	Ganga Delta, Mumbai, and other urban areas are most affected.
Global Pattern	Slum residents globally are 32% more likely to live in floodplains.
Other Countries	Indonesia, Bangladesh, Pakistan also have high slum-flood risk zones.
Impact	Displacement, job loss, poor access to sanitation, healthcare, and education.

Flood Risk Drivers in India

Factor	Impact
Riverine Floods	Overflow in Ganga, Brahmaputra, Krishna basins due to heavy rains.
Urban Expansion	Cities like Mumbai, Bengaluru encroach into floodplains.
Flash Floods	Rising due to extreme rain and saturated soil—184 cases in 2022.
Climate Change	Extreme rainfall doubled (1981–2020), monsoon intensified by 56%.
Poor Drainage	Outdated systems in metros cause urban waterlogging.
Plastic and Encroachment	Blocked stormwater drains worsen floods (e.g., Chennai 2015).
Strategy Gaps	Lack of region-specific risk plans and forecasting systems.

Slum Scenario in India

Indicator	Details
Definition	Compact housing with poor amenities; defined by Pranab Sen Committee (2010).
Population	17% of urban India lives in slums (2011 Census).
State Trends	High slum numbers in Maharashtra, UP, Andhra Pradesh, West Bengal.
Governance	Housing is a State subject; Slum Clearance Act (1956) applies to UTs.
UN-HABITAT Criteria	Slums lack durability, sanitation, clean water, tenure.

Government Schemes for Slum Development

Scheme	Focus
PMAY-Urban	Pucca housing with amenities for slum dwellers—29 lakh units sanctioned.
AMRUT & Smart Cities Mission	Improve urban infrastructure including drainage, water supply.
Swachh Bharat Mission – Urban 2.0	Waste-free city focus; targets sanitation in slums.

Sustainable Solutions for Slum & Flood Management

Strategy	Description
Region-Based Flood Plans	NDMP promotes topography-based flood risk strategies.
Zoning Laws	Prevent urban expansion into floodplains.
SUDS (Sustainable Urban Drainage)	Green spaces, rain gardens, permeable pavements to absorb rainwater.
Slum Upgradation	Elevated housing, better drainage under PMAY.
Data-Driven Monitoring	NRSC, IMD, IFLOWS/CFLOWS for mapping and forecasting.
Sponge City Model	Adopted in Shanghai and now Mumbai—manages water via green infrastructure.
Water Body Restoration	Lakes like Jakkur (Bengaluru) showcase eco-restoration for flood control.

In a nutshell

Memory Code: “FLOOD SLUM”
Flash floods rising,
Low-lying floodplains occupied,
Overcrowding in cities,
Outdated drainage,
Data-driven solutions needed,
Sponge City concept,
Lakes restored,
Upgrade slums,
Monitored risk via tech.

Prelims Practice Questions

1. Which of the following is a key feature of the Sponge City concept?
   (a) Construction of high concrete embankments
   (b) Use of artificial lakes in urban centers
   (c) Use of permeable surfaces and green infrastructure to manage rainwater
   (d) Construction of vertical housing to prevent urban sprawl
2. According to the recent Nature Cities study, India’s slum clusters are particularly vulnerable due to:
   (a) High altitude settlements
   (b) Lack of job opportunities
   (c) Concentration in flood-prone areas
   (d) Excess forest clearance
3. Which of the following cities is adopting the Sponge City model for flood management?
   (a) Delhi
   (b) Mumbai
   (c) Varanasi
   (d) Kolkata

Mains Questions

1. Discuss the major factors responsible for increasing flood vulnerability in urban slum areas of India. (15 marks)
2. Examine the relevance of the Sponge City concept for Indian cities in the context of urban flooding. (10 marks)

Answer Key with Explanations

Q No.	Answer	Explanation
1	(c)	The Sponge City concept uses green infrastructure like permeable pavements, rain gardens to manage stormwater.
2	(c)	India’s slum dwellers, over 158 million, are heavily concentrated in flood-prone areas.
3	(b)	Mumbai is implementing Sponge City features to manage floods and groundwater recharge.