India's AQI issues mostly stem from crop burning. AFAIK cars have to comply with BS6 which is pretty similar to Euro 6.
If pollution is caused by "crop burning", why is it that the worst pollution is in cities?
> The phenomenon is made possible by a dramatic improvement in air quality in recent weeks, after industries shut down, cars came off the road and airlines canceled flights in response to the coronavirus pandemic.
> Delhi saw up to a 44% reduction in PM10 air pollution levels on the first day of its restrictions, India’s Central Pollution Control Board found. The PM10 standard measures airborne particulates 10 micrometers or smaller in diameter.
https://edition.cnn.com/travel/article/himalayas-visible-loc...
The worst pollution is not in any cities. It's a problem specific to North Indian cities and regions in Pakistan.
No city in South India is even remotely as polluted as the NCR.