Geographies in Depth

India is overtaking China as the biggest emitter of this deadly air pollutant

A woman walks across a field on a smoggy morning in New Delhi, India, November 13, 2017. REUTERS/Saumya Khandelwal     TPX IMAGES OF THE DAY

India's air pollution is worsening now that they are the biggest emitter of sulfur dioxide in the world Image: REUTERS/Saumya Khandelwal

Echo Huang
Reporter, Quartz
Our Impact
What's the World Economic Forum doing to accelerate action on Geographies in Depth?
The Big Picture
Explore and monitor how China is affecting economies, industries and global issues
A hand holding a looking glass by a lake
Crowdsource Innovation
Get involved with our crowdsourced digital platform to deliver impact at scale
Stay up to date:


This week, air pollution forced some 4,000 schools to close in New Delhi, as India’s capital suffers through an air quality nightmare. Now, here’s more bad news on the pollution front: the country is passing China as the world’s biggest emitter of deadly man-made sulfur dioxide (SO2).

According to a University of Maryland-led study published in Nature on Thursday (Nov. 9), China’s SO2 emissions have fallen 75% since 2007, while India’s emissions have increased 50% in the same period. That puts India on track to overtake China, the world’s largest SO2 emitter since 2005—if it hasn’t already.

India overtook the US in 2010 to become the world’s second-largest SO2 emitter, and became the world’s second-largest consumer of coal last year. Coal typically contains up to 3% sulfur by weight, and burning coal creates SO2, a toxic pollutant that contributed significantly to the 1952 London smog crisis that hospitalized more than 150,000, as well as the haze that hovers over many Indian and Chinese cities, stealing years from peoples’ lives.

Using NASA satellite data, as well as data from primary emitters (such as power plants), researchers from the US and Canada estimated SO2 emission ranges for India and China from 2005 to 2016. Their estimates showed China’s SO2 emissions to be far lower now than earlier projections had estimated—possibly as much as four times lower—while India’s was more in line with what had been estimated. They concluded that the different trajectories were largely due to national policies related to coal-fired power plants, the major contributors to SO2, and to strict emissions controls implemented by China.

The estimates for India for 2016 ranged between 9.5 and 12.6 (pdf, p.2) megatons, while the estimates for China ranged between 7.5 and 11.6 megatons.

Image: Quartz

Yet, the number of people living close to substantial SO2 pollution still remains lower in India than in China. Substantial is defined in the paper as people living with an SO2 concentration of around 14 micrograms per cubic meter (μg/m3), compared to the WHO’s 20 μg/m3 for a 24-hour mean. Some 33 million people in India live with substantial SO2 pollution, compared with China’s 99 million, according to the study.

Researchers say they chose the 14 μg/m3 concentration because at that level the toxic gas could already affect human health (pdf, p. 4).

China has been particularly aggressive in recent years in trying to curb its notorious air pollution. It has built its coal plants to higher emissions standards, and also tried to wean homes and industry off coal. This winter it plans to heat four million homes with natural gas instead, and has asked steel producers in major producing hubs to reduce by one-third (paywall) their coking coal production.

India, however, has lagged on this front. It has been on a building spree(paywall) to put up more coal-fired power plants in recent years. Still, India is also turning to a greener economy, with investments in renewable energy. Coal India, which accounts for 80% of the country’s coal production, in April lowered its production target for its current financial year by 10% in the face of weaker demand.

Don't miss any update on this topic

Create a free account and access your personalized content collection with our latest publications and analyses.

Sign up for free

License and Republishing

World Economic Forum articles may be republished in accordance with the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Public License, and in accordance with our Terms of Use.

The views expressed in this article are those of the author alone and not the World Economic Forum.

Related topics:
Geographies in DepthNature and Biodiversity
World Economic Forum logo
Global Agenda

The Agenda Weekly

A weekly update of the most important issues driving the global agenda

Subscribe today

You can unsubscribe at any time using the link in our emails. For more details, review our privacy policy.

Digital public infrastructure is transforming lives in Pakistan. Here's how 

Tariq Malik and Prerna Saxena

July 12, 2024

About Us



Partners & Members

  • Sign in
  • Join Us

Language Editions

Privacy Policy & Terms of Service

© 2024 World Economic Forum