Countries with the Most Air Pollution

Taiwan to some is considered a part of China, not a country... yet.

Taiwan actually cleaned up its pollution problems over the past decade. They are a world leader in recycling, and generate much less air pollution now that most factories have moved to China

Kathmandu is horrifically polluted. The biggest reason is unregulated car emissions, but it's exacerbated by general lack of development: they still use do things like use chimneyed cooking stoves and burn their trash. Yet there's still a huge population growth rate, and with money brought in by Everest climbers and the Tibetan religious refugees' followers/students (who are white, Western, and affluent),there are always development/construction projects going on, which stirs up tons of dust (Nepal isn't exactly lush). I don't know if Kathmandu itself is bad enough to drag the whole country's average down or if the whole country is just socked in by weather patterns, but either way, take an industrial-strength gas mask with you.

The oil money all goes to their country's insanely disproportionate 1%, who buy giant mansions in places like Monaco, the US, and Switzerland, garages full of priceless cars, yachts, private planes, and hotels in Beverly Hills – then spend most of their time out of the country frolicking. They don't give a flying turd about improving infrastructure or the plight of the poor in their home country (even if they're the rulers too, which often is the case).