Chief Minister Sheila Dikshit on Thursday launched the Delhi Jal Board’s ambitious water pollution abatement project in Nangloi to clean up the Yamuna within three years. The interceptor sewer project aims to lay 60-km sewers parallel to Delhi’s three major drains — Najafgarh, Shahdara and Supplementary — at a depth of 20 to 60 feet and in sizes varying from 600 mm to 2,400 mm diameter. The parallel sewers will intercept about 135 minor drains and convey the waste to the nearest sewage treatment plant (STP). This will ensure that only treated sewage is discharged in to Yamuna.