This technique involves laying 50 km of interceptors, 2-3 metres in diameter, to intercept 150 small drains discharging into three major drains in the Capital-Najafgarh, Supplementary and Shahadra. 

The Delhi Government on Monday signed a Memorandum of Understanding (MoU) with Engineers India Limited (EIL) to lay interceptor sewers. The Government will spend about Rs 1,150 crore to clean the 50-km-stretch of Yamuna from Wazirabad barrage to Okhla in two phases. According to figures, the Delhi Government had already spent Rs 1,100 crore in Clean Yamuna campaign in the past one decade. The MoU was signed between the Delhi Jal Board and the EIL. 
 
The three drains contribute 70 per cent of the discharge of 3,600 million litres a day (MLD) of sewage into the Yamuna. Another 13 smaller drains will be tapped into sewers under rehabilitation into Bela Road and Ring Road Trunk Sewer. The sewage from more than 1539 odd unauthorised colonies and other unsewered areas would be trapped before it is permitted to reach all the major drains. 
  
With this the total expenditure on cleaning the Yamuna by the year 2010 is estimated to be Rs 2,300 crore. 
 
As per the plan the work is to be carried out in two phases. In the first phase, it will build interceptors along the Najafgarh and supplementary drains, while in the second phase, interceptor sewers will be built along the Shahadra drain and it involves augmentation of sewage treatment plan at the moth of Delhi Gate drain and Dr Sen Nursing Home drain.
 
Acknowledging that Yamuna had over the years turned into a "dirty river" from which even birds and animals did not drink water, Chief Minister Sheila Dikshit said work for cleaning it occupied top priority of the Government in view of the 2010 Commonwealth Games and the need for clean drinking water for people of the city. 

"Ensuring a clean Yamuna is critical and very important. First, because of the approaching Games and, second, Delhi needs clean drinking water," the Chief Minister said on the occasion of the signing of the agreement. 

Through this initiative, the DJB envisages making the river as clean as the Thames in southern England. Acknowledging that the pollution levels in the river had risen considerably over the years, Dikshit said, " the Yamuna has become very dirty, prompting many to call it the Drain of Delhi. If one looks at the river, one almost feels like crying. Touching it gives one a tingling feeling. In fact, it looks like an acid pond," the Chief Minister said.