Smokescreens were widely used as a defensive tactic during World War 2. Assuming that the bombing crews are attempting to hit a target rather than just indiscri

Smokescreens were widely used as a defensive tactic during World War 2. Assuming that the bombing crews are attempting to hit a target rather than just indiscriminately bomb an area of several square kilometers, they were very effective before the advent of infrared cameras all-weather radar. Smokescreens do require relatively calm winds though. You could e.g. read "Target Tirpitz" which is a historical account documenting among other things how smokescreens were used to defend Germany's biggest battleship against a large number of bombing runs. A battleship is pretty much the biggest target you could have on a battlefield, showing that this tactic is very effective against non-indiscriminate bombing.