Delhi AQI: With IIT Study Stalled, What Does Data Say About Causes Of Pollution?

What is the IIT-Kanpur study and why has it snowballed into a political tussle? The Quint explains.

In a letter addressed to Chief Minister Arvind Kejriwal, Rai called for Kumar's suspension for halting the study by questioning the project cost and the findings of the study. Image used for representative purposes. 

(Photo: The Quint)

As Delhi's air-quality levels deteriorated this week, a first-of-its kind study to ascertain the causes behind the city's polluted air has allegedly been stalled on the orders of Delhi Pollution Control Committee (DPCC) chairman Ashwini Kumar, said Environment Minister Gopal Rai on Wednesday, 25 October.

In 2021, the Delhi government, in collaboration with the Indian Institute of Technology (IIT) Kanpur decided to conduct a study on the "Real-Time Source Apportionment" of pollution in the city.

But what have earlier studies said on the causes leading to Delhi pollution? Why has it snowballed into a political tussle? FIT explains.

What Is The IIT-Kanpur Study?

Among all the cities in the world, some of the worst levels of air pollution are seen in Delhi. According to the World Air Quality Report prepared by IQAir, Delhi ranked fourth on a list of 50 of the world’s most polluted cities in terms of PM2.5 levels in 2022.

According to the AAP government, there was a need to identify real-time sources of pollution so corrective action could be taken across the most polluting sectors on each day.

In October 2021, a Memorandum of Understanding (MoU) was signed between IIT-Kanpur and DPCC at a cost of Rs 12.72 crore. In January 2023, a real-time source apportionment and pollution forecasting system was also set up in Delhi in collaboration with IIT-Kanpur, IIT-Delhi, and The Energy & Resources Institute (TERI).

According to the Dialogue and Developmental Commission (DDC) of the Delhi Government, the key objectives of the study are:

• To help understand the real-time effect of various pollution sources like vehicles, dust, biomass burning, stubble burning, and smoke emanating from factories.

• To provide daily and weekly forecasting of air quality and Air Quality Index (AQI) at multiple locations, within and outside Delhi, and real-time diurnal source apportionment.

The findings of the study, however, are yet to be made public. In a nutshell, this is also what led to a tussle.

What Do Existing Studies Say On Causes Of Delhi Pollution?

This isn't the first time that a study on the causes of Delhi pollution has been undertaken. In the last decade, at least two source apportionment studies have been carried out by IIT-Kanpur and The Energy and Resources Institute (TERI) to identify the contribution of each sector to Delhi pollution.

In both studies, biomass burning, industries and transport sector, were the biggest sources of pollution.

In the 2016 IIT-Kanpur study, commissioned by the Delhi government, biomass burning (26 percent) was identified as the primary source of PM 2.5 pollution in the winter, followed by vehicles (25 percent).

The study also stated that secondary pollutants (30 percent) –formed when pollutants and gases mix – were a major cause of PM 2.5 particles in the air during the winter.

"The winter sources (percent contribution given in parenthesis for PM10 - PM2.5) include: secondary particles (25 - 30 percent), vehicles (20 - 25 percent), biomass burning (17 – 26 percent), MSW burning (9 - 8 percent) and to a lesser extent soil and road dust. It is noteworthy, in winter; major sources for PM10 and PM2.5 are generally the same," the IIT-Kanpur study stated.

Pollution From Vehicles in Focus

Meanwhile, TERI's study in 2018 showed that the average contribution of Delhi’s own emissions in the city's PM2.5 concentrations was found to be 36 percent in winters and 26 percent in summers.

The study identified industries (30 percent), including thermal power plants as the source of PM 2.5 pollution in winters, followed by vehicles (28 percent).

In 2017, Centre for Policy Research (CPR) study attributed pollution to reasons including vehicle exhaust (30 percent), biomass burning (20 percent), heavy industry (15 percent) such as power generation, small-scale industries like brick kilns, suspended dust on the roads due to vehicle movement and construction activities (20 percent), open waste burning, combustion of fuels for cooking, lighting, and heating, and in-situ power generation via diesel generator sets (10 percent).

"Extreme air pollution from these sources affects millions of people in densely populated regions who are exposed to thick, toxic smog for long periods of time," the study had said.

In 2023, a collaborative study led by IIT-Kanpur found that the high amount of particulate pollution in Delhi during nightly hours was caused by biomass burning emissions.

"Air pollution is responsible for 18 percent of the total annual premature deaths in India. Uncontrolled biomass burning for residential heating and cooking in the Indo–Gangetic plain gives rise to ultrafine particles, affecting the health of 5 percent of the world’s population," the January 2023 study, published in Nature Geoscience journal said.

What Is The Political Tussle Around The Study?

For years, Delhi has witnessed a blame-game between its elected government and Centre over causes of pollution. While the former has been stating that the sources of air pollution lie outside the city, caused by stubble burning in the neighbouring states of Punjab and Haryana, the Centre cited local pollutants as the main reason.

However, the tussle at present is due to a disagreement between DPCC's chairman and the government on the findings and funding of the study over the last week.

In his press conference held on Wednesday, Gopal Rai had said that the first instalment of Rs 10.72 crore was released to IIT-Kanpur once the MoU was signed.

However, Rai claimed that when Ashwini Kumar was appointed DPCC chairman in December 2022, the latter had expressed concerns about the “substantial expenses associated with the study."

After several back-and-forth meetings with IIT-K scientists, Kumar allegedly issued orders on 18 October to stop the release of the remaining Rs 2 crore funds to the institute, effectively cancelling the study, Rai said.

In response to Rai's allegations, a senior DPCC official told The Indian Express, “Validation should be able to predict future outcomes based on the findings. This was not provided satisfactorily. The report tries to portray that Delhi’s pollution is not its doing and other states are to blame. This may be the case during the stubble burning season but is not during the rest of the year. It is a red herring aimed at helping people escape accountability."