New Delhi, Oct 7 (IANS): Challenging MCD data on commercial vehicles entering the capital each day, a CSE study released on Tuesday said the civic body's figures were 70 percent less than the actual and could lead to gross underestimation of pollution level and weaken action to combat it.

"Without the right numbers, official action to control truck pollution will remain weak and ineffective," Centre for Science and Environment (CSE) Director General Sunita Narain said a press conference here.

According to MCD data, on an average, only 22,628 commercial vehicles, excluding taxis, enter Delhi per day from nine entry points, as against 38,588 commercial vehicles counted by the city-based research and advocacy organisation CSE survey -an underestimate of about 70 percent, the study said.

The study said a large numbers of trucks, which pass through Delhi to avoid higher toll charges on other routes, were running on outdated technology, "spewing smoke and make Delhi polluted".

"The MCD estimate of the number of trucks crossing Delhi borders is grossly underestimated and is unreliable for calculating pollution load from trucks," the study said, adding the gap at different entry points varies in the range of 50-96 percent.

The traffic count survey used round-the-clock video recording at fixed spots near selected entry points between June 29 and July 18, 2015.