Complex sentence: Four years later, the Indian Physics Association awarded Sreekantan the R. D. Birla Memorial Award and the Government of India awarded him the third highest civilian honour of Padma Bhushan in 1988.
Split into simpler sentences: Four years later, the Indian Physics Association awarded Sreekantan the R. D. Birla Memorial Award. He has received four awards from various governments, starting with the the third highest civilian honour of Padma Bhushan from the Government of India in 1988.