PM2.5 levels – fine particles with a diameter of 2.5 microns or less, which can penetrate deep into the lungs and even enter the bloodstream, posing serious health risks such as respiratory and cardiovascular diseases – increased in 154 cities this summer compared to summer 2023. Conversely, 88 cities saw a decrease in PM2.5 levels, and 27 cities did not have monitoring systems installed or recorded no data last summer.
Additionally, the average PM2.5 in 35 cities exceeded the limit of 60 micrograms per cubic metre (µg/m³) set by the National Ambient Air Quality Standards (NAAQS). The analysis, conducted between April and June 2024 by Pune-based Respirer Living Sciences (Respirer), used primary data collected from the Central Pollution Control Board (CPCB) portal to assess air quality during these summer months.
“Our results indicate a significant increase in PM2.5 levels in many cities this summer, challenging the perception that air pollution is only a winter problem,” said Ronak Sutaria, CEO and founder of Respirer.
City ranking: Assam’s Byrnihat recorded worst PM2.5 levels this summer
Data from Respirer’s analytics platform AtlasAQ showed that Byrnihat, located near the Meghalaya-Assam border, recorded the highest average PM2.5 levels of 116.35 µg/m³, placing it in the ‘poor’ category, according to the CPCB. Despite being part of the National Clean Air Programme (NCAP), Byrnihat’s levels exceeded the NAAQS limit on about 73 per cent of summer days. However, it managed to reduce its summer PM2.5 levels by about 17 per cent compared to summer 2023.
“The high pollution levels in Byrnihat highlight the growing air quality crisis in northeast India, caused by industrial activities and inadequate pollution controls. The industrial city… has recorded high pollution levels throughout the year, and even during the summer,” Sutaria said.
Faridabad and Gurugram in the National Capital Region followed Byrnihat with averages of 104.88 and 95.5 µg/m³ respectively, both categorized as ‘poor’. Faridabad saw a substantial increase in PM2.5 levels of 94.9 per cent from ‘satisfactory’ to ‘poor’. “This increase is attributed to vehicular activity, construction dust and meteorological factors prevailing in the National Capital Region,” Sutaria said.
The role of industrial activities, combined with increasing urbanization, is the main cause of high summer pollution. “The increase in pollution levels in regions like the NCR highlights the need for stricter measures and constant monitoring throughout the year,” Sutaria added. “It is essential to implement and enforce policies that can mitigate these problems, especially during the summer months.”
Tirupur in Tamil Nadu is among the cleanest cities, with PM2.5 levels of just 12 µg/m³. This stark contrast highlights the differences in air quality across India.
The 10 most polluted cities in summer 2024 in terms of PM2.5 levels are:
Byrnihat, Assam: 116.36 µg/m³
Faridabad, Haryana: 104.88 µg/m³
Gurugram, Haryana: 95.56 µg/m³
Mandi Gobindgarh, Punjab: 92.21 µg/m³
Ballabgarh, Haryana: 90.35 µg/m³
Muzaffarnagar, Uttar Pradesh: 85.11 µg/m³
Sri Ganganagar, Rajasthan: 85.03 µg/m³
Charkhi Dadri, Haryana: 84.51 µg/m³
Patna, Bihar: 82.87 µg/m³
Rohtak, Haryana: 81.76 µg/m³
45% of NCAP cities recorded an increase in PM2.5 during summer 2024
The NCAP, launched in 2019, is a long-term, time-bound strategy that targets a 20-30% reduction in PM2.5 and PM10 levels by 2024, using 2017 as the baseline year. Extended to 2026 with a 40% reduction target, the NCAP focuses on 131 non-compliant cities, those that have failed to consistently meet the NAAQS standards, and implements city-specific action plans.
Of the 131 NCAP cities, data was available for 100 cities on the CPCB website, according to Respirer’s analysis. Of these, 59 cities, or 45 per cent, recorded an increase in PM2.5 levels, while 31 recorded a decrease compared to the previous summer. Monitoring stations were not available for the remaining cities the previous year.
“After five years of NCAP, the limited surveillance coverage of only 75% of NCAP cities with reliable and comparable long-term surveillance data also reflects the fact that the existing surveillance network is not adequate. Scientifically validated and scalable alternative solutions need to be adopted to gain an urgent and immediate understanding of the scale and magnitude of the challenge that affects us every day,” Sutaria said.
Delhi, ranked 13th overall and 6th among NCAP cities with a PM2.5 value of 79.25 µg/m³, saw a 22.4% increase compared to last summer.
“These results from NCAP cities reveal that despite continued efforts, air quality continues to deteriorate in many areas. Separate surveys must be part of cities’ action plans to identify and address major sources of pollution in each city,” Sutaria added.
Worrying trend regarding multiple pollutants in various regions during summer
In addition to PM2.5, Breathe monitored several other pollutants including particulate matter (PM10 – coarser particles of 10 microns), nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO) and ozone in cities.
The results reveal worrying trends that go beyond fine particles. For example, Sri Ganganagar in Rajasthan recorded the highest levels of PM10, increasing by 21% from the previous year to 298 µg/m³, making it the most polluted city in terms of PM10 this summer.
The analysis also showed a significant increase in NO2 levels, with Chengalpattu in Tamil Nadu and Dhanbad in Jharkhand seeing substantial increases of 593% and 505%, respectively. SO2 levels, though below the NAAQS limit, increased in Imphal, Manipur and Raichur, Karnataka. CO jumped in Vijayapura, Karnataka, and Siwan, Bihar, reflecting the deteriorating air quality. Ozone, another critical pollutant, increased in 127 out of 262 cities, with Baddi in Himachal Pradesh and Ujjain in Madhya Pradesh showing sharp increases.
“The increase in NO2 is mainly due to increased industrial activities and traffic emissions, while SO2 is linked to industrial emissions and coal combustion. Meanwhile, the increase in CO can be attributed to vehicle emissions and urban sprawl, while the sharp increase in ozone is likely due to rising temperatures and automobile pollution,” Sutaria explained.
The latest State of Global Air 2024 report shows that air pollution remains a critical health risk in India, being the second leading risk factor for death globally and responsible for 8.1 million deaths in 2021. This includes deaths from non-communicable diseases such as heart disease, stroke, diabetes, lung cancer and COPD. For the first time, the report includes data on exposure to NO2, highlighting its impact in densely populated urban areas where traffic emissions are high. South Asia, including India, is one of the regions most affected by health impacts related to air pollution.
Air pollution leading cause of cardiovascular deaths in India, doctors say
Air pollution has become the leading cause of cardiovascular deaths in India, surpassing traditional risk factors such as hypertension, diabetes and lipid profile, doctors said.
BB Bharati, executive committee member of the Indian Society of Cardiology, said the alarming rise in heart attacks among young people can be partly attributed to air pollution. “Heart attacks among young people are occurring 10 times more frequently than a decade ago, mainly due to air pollution. If current trends continue, India is set to overtake China as the country most affected by air pollution-related health problems,” he said.
