One-third of Delhi's PM2.5 comes from a sneaky source, says study
Turns out, about a third of Delhi's air pollution (PM2.5) is from secondary ammonium sulfate—a compound formed when emissions from coal plants and factories mix with farm ammonia, especially in humid weather.
Why does this matter?
Ammonium sulfate spikes during Delhi's worst pollution months—making up nearly half of PM2.5 after monsoon and in winter, but less in summer.
If you live near a coal plant (within 10km), levels are even higher.
It's not just Delhi—this is a national problem
Across India, ammonium sulfate makes up over a third of PM2.5 pollution and can reach 42% in some places.
Most sulfur dioxide fueling this comes from coal plants, mainly in Chhattisgarh and Odisha.
So what's the fix?
The CREA report points out that most coal plants don't have to clean their emissions right now.
They're urging for stricter rules—like bringing back the 2015 standards—to cut down on this hidden source of dirty air.