No sewers in 2 out of 5 Delhi homes
Here is a statistic from Census 2011 that will leave you shocked : 40% of Delhi's population - about 67 lakh people - lives in homes that do not have closed drains to take away waste water. In fact, they are not connected to the sewerage system at all. Toilets in these homes are mostly connected to septic tanks, and waste water from bathrooms etc flows into open drains.
Where are these people? Most of them live in the vast northern periphery of Delhi. In North East district, 73% of the population lives in homes with open drains. In North West district, 45% don't have closed drains. In the South district too 40% don't have proper drains. It is only in the central core of Delhi that the situation is somewhat reasonable.
Living near open drains, which probably get clogged and overflow periodically is a severe health hazard that hits quality of life. In 2001, 65% of the urban population of Delhi was covered under sewerage network. This declined to 55% in 2011, according to analysis done by National Capital Region Planning Board (NCRPB).
There is another side to this dismal story. According to NCRPB, Delhi generates about 4,528 million litres of sewage every day but the sewer network manages to intercept only about 2,280 million litres. The reason is fairly straightforward - the sewer network does not reach about half of Delhi's population. So, the unintercepted sewerage flows straight into water bodies or reaches the Yamuna river through storm water drains.
The 31 sewage treatment plants (STPs) in Delhi, which have a combined capacity of 2,475 million litres of sewage per day, actually treat only 1,589 mld. Between 2001 and 2011, the amount of sewage treated has increased from 1,500 mld to 1,589 mld - just 6%.
The reason why these expensive STPs are lying idle is simple. The sewage just does not reach the plants. A recent report of the Comptroller and Auditor General (CAG) pointed out that Delhi Jal Board (DJB) spent Rs 2,715 crore building STPs and sewers. The CAG criticized DJB, saying that increasing capacity of STPs was beyond justification.
In 2008, a new idea was floated. If homes could not be connected to sewers, at least some of the sewage flowing in the storm water drains towards the river could be collected and treated. Called the 'interceptor sewer system', it was hoped that by this means another 31% of Delhi's population would come under sewerage system, though indirectly.
What happened next is typical of Delhi's callousness. Engineers India Limited was appointed to prepare a project, which it did. The report said the project could be finished by September 2010. The government sat on the proposal for three years and it was finally awarded in July 2011 to be completed by 2014. Meanwhile, it turns out that STPs may find it difficult to treat the intercepted sewage during monsoon months as a large amount of rainwater would be mixed with it.
with thanks : Times of India : LINK