Drainage and sewerage system in urban India

Need for action

Dear Sir,

The recent issue has highlighted some facts about urban sanitation in India.[¹] Drainage and sewerage system in urban areas is an important priority in Indian setting because of rapid urbanization, industrialization, and population growth, along with increase in slum population and migration. A recent study showed that sewerage systems typically reduce diarrhea incidence by about 30% or perhaps as much as 60% when starting sanitation conditions are very poor. But in many contexts, sewerage might be less cost effective and less sustainable than onsite alternatives.[²] Another study also showed that urban sanitation can have an impact on diarrheal disease, even without measures to promote hygiene behavior.[³] In this regard, the presence of efficient drainage and sewerage system is a major factor in the prevention of spread of waterborne diseases in major cities. As per the census 2011, at country level, there is no drainage facility in 48.9% households, while 33% households have only open drainage system.[⁴] National Family health Survey-3 (2005-2006) reported that 52.8% of the households in urban areas have ′improved sanitation′ which means that their flush or pour toilet latrine connected to piped sewer or septic or other systems, while 41% of the households still have no latrine within household premises, with 24.2% of them depending on public latrine and other 16.8% practising open defecation. Besides, more than 28% of the urban population lives in slum areas. In Bangalore, Karnataka, only half of 52 towns were served by a sewerage system, while in Hyderabad, Andhra Pradesh, 86 of 124 towns had neither sewerage systems nor running water. The bulk of sewage treatment capacity exists in the metropolitan cities, with 40% of wastewater generation. The cities of Delhi and Mumbai generate some 17% of all the sewage in the country.[⁵]

Treatment of wastewater is one of the important steps to prevent contamination of urban underground water.[⁶] Because of unpredictable growth and regional shortage of water, urban areas may be monitored with semi-centralized supply and treatment system of wastewater.[⁷] The change from centralized to semi-centralized supply and treatment systems will minimize the grave discrepancy between the rapid urban growth and the provision of supply and treatment infrastructure.[⁸] A case study from India showed that converting the existing open wastewater collection drains on the roadsides, as decentralized networks of covered drains, and converting the large open drains on the outskirts of suburban areas that carry wastewater to agricultural fields is 70% cheaper compared to conventional collection and treatment systems.[⁹]

National Urban Health Mission is a welcome step and recent development which will be launched with focus on slum areas and other urban poor.[¹⁰] At the state level, there would be a State Urban Health Programme Committee, at the district level, a District Urban Health Committee, and at the city level, a Health and Sanitation Planning Committee. At the ward slum level, there will be a Slum Cluster Health and Water and Sanitation Committee. Involvement of local community in planning, implementation, and monitoring of sanitation activities, development of cost-effective and efficient methods and its delivery system to improve the sanitation for rapidly growing urban population, involvement of NGOs, local leaders, and other stakeholders, adequate financing, and political commitment are the requisite areas to be considered to improve the sanitation status in urban areas.