Delhi: Early warning system works amid AQI spike | Latest News India

On four of the last six days up to Friday, Delhi's Air Quality Early Warning System (EWS), which uses “various satellite data sets” and is “based on state-of-the-art atmospheric chemical transport models,” made incorrect predictions. For example, on October 13, air quality was forecast to be “moderate,” but the air quality index (AQI) was well at “poor.” The next day, when improvement was predicted, the situation worsened and the AQI deteriorated further into the poor zone.

This is not new.

In 2023, when the city had its first “severe” day of air pollution on November 2nd (the AQI shot past the frightening figure of 400), the EWS missed the signs by a significant margin by six days – that's when it had predicted the AQI would only be slipping into the deep red area on November 9th.

The EWS was launched in October 2018 to provide air quality warnings up to ten days in advance. It has a worrying track record: Citizens are uninformed about when to take precautions to deal with the annual public health crisis, and authorities have been unable to announce containment measures that could prevent some of the worsening or at least allow them to react more quickly to the conditions.

To illustrate the consequence of a recent example: the Commission on Air Quality Management (CAQM) decided on October 13 not to apply the first stage of pollution-related restrictions, citing the EWS forecast that the air at would improve the following day. But the air worsened, prompting CAQM to hastily introduce restrictions on October 14.

The project is led by the Indian Institute of Tropical Meteorology (IITM), Pune, and comes under the Union Ministry of Earth Sciences. Along with another model called the Decision Support System (DSS), which tracks farm fires in the nearby states of Punjab and Haryana, the EWS feeds intelligence used by the Commission for Air Quality Management (CAQM), which is then tiered Response measures decide The plan (Grap) to restrict activities is enforced.

While these projects and committees have evolved over the years – both in nature and in their authority – little has changed on the ground. Last year, Delhi witnessed its third busiest November with an average AQI of 373. If you ignore a few outlier days where rain helped lower pollution, the average AQI in November would actually be around 390, which is actually enough to make it the most polluted country anywhere.

HT spoke to officials involved in the EWS project who admitted that the system does not adequately take into account emissions and weather factors and is prone to errors when incorrect data is fed, particularly from meteorological sources.

“Forecasts and actual AQI may differ if positive measures are taken on site. The system is also dependent on meteorological conditions and the forecasts provided to us and received by the system. If meteorological conditions change suddenly, forecasts can inevitably go wrong,” said an official at the Indian Institute of Tropical Meteorology, asking not to be named.

The IITM official working on the model said no changes have been made in the system since last year.

EWS consists of two models – a weather forecast model supported by IMD and an atmospheric chemical transport model. Both models collect data from Delhi's air quality monitoring stations, satellite images and IMD forecasts. These models are intended to determine whether local emissions are increasing or decreasing, which aerosols are in the air, the effects of widespread dust storms and the contribution of pollutants from agricultural operations. These determinations are then simplified into an AQI forecast for the next few days.

Of course, IMD itself is notorious for regularly getting its predictions wrong. In June 2021, HT analyzed IMD's long-term forecasts and found that they are correct only 50% of the time.

Madhavan Rajeevan, former secretary of the Union Ministry of Earth Sciences (MoES), said that while EWS is a good start, there is room for improvement. “We are gradually improving it, but this is certainly not the final product. We need more data from outside Delhi as there are still many unaccounted sources that inevitably go unaccounted for in the models and thus can impact the forecasts,” he said.

Experts say EWS's failures are emblematic of the ineffectiveness of measures to tackle the air pollution crisis that has become a defining image of India's capital over the past decade.

Mukesh Khare, an air pollution expert from IIT Delhi, said that even with the use of the EWS and the introduction of Grap, such “short-term ad hoc measures” would do little to help Delhi's AQI in the long run. “CAQM was founded to focus on both short-term and long-term measures. So far we have seen very little long-term action, and unless there is aggressive, year-round action, little will change,” he said.

Another climatologist who works independently said it was crucial to review the model and consider increasing the reference range to account for more sources.

“Air pollution in Delhi doesn’t just come from within the city. We have incursions from neighboring cities. Thermal power plants are still operating within 300 km of Delhi, even though there are no coal-fired power plants in Delhi – and even the far-flung power plants can carry pollution over long distances. There is a need to consider a large geographical area and ensure that every source there is mapped,” said Sunil Dahiya, founder and principal analyst at Envirocatalysts.