The drones will monitor companies who emit pollutants judging offending smokestacks by the color of their emissions.
"You can easily tell from the color of the smoke -- black, purple, and brown -- that the pollution is over the limit, because if the smokestack scrubbers are operating properly, only white smoke is emitted." said Chinese official Yang Yipeng.
If the drones find pollutants, they will spray chemicals to freeze the pollutants to prevent them from falling to the ground. This is part of what the Chinese premier calls the "War on Pollution."