DSS running again, but will not affect pollution decisions in Delhi

New Delhi

The Decision Support System (DSS) under the Union ministry of Earth sciences (MoES) resumed functioning on Monday, sharing data on sources that were impacting Delhi’s air quality—over a week after it stopped updating information on its website. The Commission for Air Quality Management (CAQM), whose subcommittee is carrying out a performance evaluation of the model, however, said that it will not use DSS to take pollution-related decisions as the emissions inventory it was using was old.

DSS was commissioned in 2018 alongside the early warning system for Delhi (EWS) by MoES and was used to only calculate the contribution of biomass burning to Delhi between 2018 and 2021. However, when CAQM was formed in 2021, it asked DSS to also look at other sources and incorporate the area outside Delhi. Presently, it shares the sources of contribution to Delhi from both within and outside the Capital, including from 19 NCR districts.

On December 4, HT reported how the model’s last update was between November 26 and 29, and a CAQM subcommittee was assessing its performance. The subcommittee had also asked the Indian Institute of Tropical Meteorology (IITM) to update the model to improve its accuracy and update its emissions inventory, which dates to 2021.

A CAQM official said: “Regional and source-wise contributions are based on the emissions inventory formulated a few years ago. For more accurate estimation of source contribution, the latest emission fields are required and refinements are still underway, for DSS to be fully commissioned. IITM is working on updating the air pollution sources and data of emission patterns.”

The official said CAQM was coordinating with IITM for the same.

An IITM official, meanwhile, said there was a “technical glitch” which impacted the model, adding it was now operational again. “We ran the model on December 8 and so, it was updated on December 9. It is being run on an experimental model. CAQM’s performance evaluation will continue and once complete, we will incorporate changes,” the official said.

According to DSS, the highest estimated contribution to Delhi’s air was PM 2.5, at 13.44%, on Monday, followed by 12.13% from the transport sector.