To what extent is the belief valid that sighting the crescent moon is difficult due to the abundance of industry, smoke, and buildings, and what is the size of the crescent moon when it first appears?

It is possible to sight the crescent moon. If it is obstructed in one location due to smoke, it can be sighted in another clearer location. Smoke and buildings are not comparable to clouds in obscuring the crescent moon. If the crescent moon is obscured and not seen, the month of Sha'ban should be completed as thirty days. When the crescent moon first appears, it is very small and can only be seen by someone with keen eyesight.