These ficus were planted a year back. They are suddenly down now. Could it be some kind of parasite infestation? The third pic is a Pongamia tree near these ficus. I was able to notice something else growing on it.. Could it be the same killing these ficus? This is in Bangalore, India.
That looks like stress on the plant. Ficus are prone to drop leaves at the first signs of change/stress especially when they are not established. If you just planted them last year and it is starting warm up now, they probably still need supplemental watering if there isn't enough rainfall yet. I am not very familiar with your climate, only what wikipedia and weather channel tells me, and it sounds like its pretty warm over there right now.
