Northern China chokes under severe pollution

Tens of millions of people across northern China were under severe pollution warnings Tuesday, with authorities urging them to reduce outdoor activities as a greyish smog enveloped the region.

Several areas of north China's Beijing-Tianjin-Hebei region, home to over 100 million people, are suffering from the worst pollution they have seen in months. Authorities urged residents to "to reduce going out and strenuous outdoor exercise in the near future."

They were also limiting the number of construction and transport vehicles allowed on the roads.Air quality monitoring firm on Tuesday listed Beijing as the fifth most-polluted major city on Earth, just ahead of Indian megalopolis Mumbai.