Unless we can encase the TajMahal is a giant glass dome, there is little that ASI can do, we cannot stop visitors, we cannot limit air pollution, we cannot stop the insects that live in the water around the Taj Mahal ( these are the ones that alleged give the greenish shade).
What we need is to have to inputs of experts around the world in terms of maintaining the ancient monuments and get a fresh practical plan to reduce the pollution.
At some hospitals, we are give disposable foot covers to be worn. These would be around 4-5 rupees each, if feasible, these can be given to visitors and add part of it to the entry ticket. We can try to have a radius of 10-20 kilometers or so which can be declared as a buffer zone for pollutants (water and air).
With regards to the ownership of such heritage sites irrespective of any religion, it should be the Government of India and the religious board together so that we do not hurt the religious sentiments and at the same time not allow them to have a free hand.