This video is called Peregrine Falcon checking out a new condo, July 2015, Singapore.
From the Bird Ecology Study Group in Singapore about this:
Many birds keep their feathers in good condition by taking dust-bath LINK. They lie on the dusty ground and moves vigorously about to get the dirt particles onto their feathers. This helps to get rid of ectoparasites as well as stale secretions from their oil glands.
In the case of this falcon, it found a quiet spot in this uncompleted high-rise building.
The presence of sand particles as a result of building activities and the absence of workers in the unit made this an ideal site for its “bath’. It would not be long before the building would be completed and no opportunity for the peregrine to return. Maybe the photographer would then have an opportunity to document other birds taking shower baths?