We are considering a project related to drones and in my discussions with people I heard that flying UAVs overhead people (crowds or otherwise) is banned. I also heard this is the case for the USA and EU. I searched and couldn't find the related detailed explanations anywhere.
I would be grateful if somebody could shed some light and point me in the right direction.
The general rule of thumb is "don't do anything hazardous for people or property on the ground".
Based on whether your project is for recreation or not, how heavy the drone is,... you may not be able to do the same things. The FAA website has a page titled ``What Can You Do With Your Unmanned Aircraft?'' that gives details on what you can and can't do based on these parameters.
A document published by EASA states that for low-risk drone operations:
Flights above crowds are prohibited, but flights above people not related to the operation in cities or populated areas is allowed.
Refer also to local laws. A number of states and municipalities have passed or are considering limitations on unmanned aircraft.
