I don't think this is true for particulate pollution. You may only be talking about carbon dioxide.
Also, "Somewhere else is worse" isn't a good defense, especially when it may not even be true; it's just deflection. India has a real problem here with air pollution, and pointing fingers at other nations won't fix it.
The person I replied to was saying that India's PM2.5 pollution is equatable to CO2 pollution done by the US. Which is really not true, plus he saw that opinion in a documentary about climate change. Which would be a valid opinion.
In my opinion, particulate matter is a problem that will be solved with a small amount of effort. And now in India it will be, we had similar scare in 1998 and Delhi became the first city in the world to convert entire public transportation plus all the for-hire auto-rickshaws to CNG.
On the other hand, an entire political party in USA denies climate change is even real. Plus, it's not a problem that will be fixed at all, we can merely contain it's effects.