New Delhi: Delhi Jal Board (DJB) has informed National Green Tribunal (NGT) that out of samples tested from 42 rainwater harvesting pits of 39 societies in Dwarka in Sept, it found faecal coliform to be at a low percentage compared to the findings of the Delhi Pollution Control Committee (DPCC), which collected samples in the pre-monsoon period.
DJB, in its report dated Dec 3, said that a previous analysis by DPCC in May, which found high faecal coliform in over 50% of the water samples, was conducted during the dry season, which could lead to contamination due to stagnation.
However, DJB identified 34 societies where the run-off was connected to rainwater harvesting pits through surface water drains, possibly leading to some form of contamination. The residential societies were informed, and five had already taken corrective action by bifurcating the surface run-off from paved areas to RWH pits, DJB said.
NGT has been hearing a plea from a resident, who claimed that rainwater harvesting pits in Dwarka were contaminating the groundwater.
In May last year, an NGT-appointed expert committee, which included members from DPCC and DJB, took samples from rainwater harvesting pits in 235 societies in Dwarka and found high ammoniacal nitrogen and high total dissolved solids in 180 societies.