Idea is to put 2L filled & sealed water bottle in every cistern of every home. Space occupied by this bottle would save 2L of water everytime flush is used. A family of 4 would typically use flush 15-20 times a day. Just imagine saving possible if all houses in Dwarka (nee whole of Delhi) practice this simple water conservation technique.
Japan has already introduced 2.5L - 4L cistern tanks. Airlines have been using such water saving devices in their toilets.
