TEHRAN (Press Shia Agency) – The Islamic Revolution Guards Corps (IRGC) dismissed concerns about clouds of white smoke seen in Tehran’s sky on Tuesday morning, saying it was caused by a military drill that included IRGC aircraft.

In a statement on Tuesday, the IRGC Aerospace Force said a “tactical exercise” by its flying objects caused the white smoke in Tehran’s sky.

The tactical drill, including fixed- and rotary-wing aircraft as well as drones, was held at one of the IRGC Aerospace Force’s bases used exclusively for exercises, it added.

 The white streaks planes leave behind are actually artificial clouds. Jets leave white trails, or contrails, in their wakes. The hot, humid exhaust from jet engines mixes with the atmosphere, which at high altitude is of much lower vapor pressure and temperature than the exhaust gas.

The water vapor contained in the jet exhaust condenses and may freeze, and this mixing process forms a cloud very similar to the one someone’s hot breath makes on a cold day.