Many places have air and water pollution. However, the place with the quantifiably worst air and water pollution is China. Earlier in 2017, the Chinese air pollution tripped a tweet that was supposed to be a joke tweet from the United States government. The small particulates that can get into your lungs are not supposed to get above 500 parts per million; well, the Chinese government has made that happen, and beyond.
They have actually raised the red alert threshold so that the red alerts won’t happen anymore. As for their water, at least half of all the water in their rivers are so polluted, it has been deemed unsafe for any kind of use - even in a fountain. Two showers a day in Hong Kong would use up your water for an entire year.