While it’s hard not to notice China’s air pollution problem from the ground, it’s an entirely different experience observing the smog from the air. When there are no buildings and limited visibility, the severity of the situation quickly becomes even more apparent.

A reporter with Chinese Business News, and frequent flier, has spent three years compiling aerial photographs taken from the window seat of an airplane. The photos show huge clouds of smog enveloping various cities around China.

Here’s a small collection along with notes about where and when each photo was taken:

Taken in Tianjin on a flight to Shenyang on December 17, 2014 (above).

Taken during descent into Shenyang on China Eastern flight MU2263 from Xi’an, on March 25, 2014.

Taken during descent into Xi’an on China Southern Airlines flight CZ6469 on March 19, 2014.

Taken after a stopover in Shijiazhuang on Beijing Capital Airlines flight JD5304 from Changchun to Xi’an on January 28, 2014.

Taken on descent into Xianyang Airport on Beijing Capital Airlines flight JD5304 from Changchun to Xi’an on December 31, 2013.

Taken above Shijiazhuang Airport on Beijing Capital Airlines flight JD5304 from Changchun to Xi’an on December 31, 2013.

Taken on descent into Xi’an on Southern China Airlines flight CZ6469 from Shenyang to Xi’an via Taiyuan on Mar 19, 2014.

Shot after taking off from Changchun Longjia Airport in which a haze can be seen enveloping the city in the distance on November 11, 2013.

If you’d like to see more pictures, here’s another collection from the beginning of last year.

Photos: Shijiazhuang Weiba