I agree that it's quite clear that environmental externalities per dollar GDP (and per dollar of exports) are massive. At the same time consider that as median incomes increase, marginal utility of clean(ish) environment vs income increases, public pressure mounts, and countries do tackle environmental externalities.

That's the story of every country's industrial development since the British industrial revolution. Bread comes first, clean water and air come second. For rich western countries to forget that and demand that China and India put environment ahead of pulling people out of poverty is myopic at best and, realistically, highly hypocritical.