Complex sentence: This school was founded by Ram Balak Mishra as upper primary school in 1973 and it came in aid list in 1981.It is upgraded to High School in 1986 and became aided in 1991.
Split into simpler sentences: This school was founded by Ram Balak Mishra as an upper primary school in 1973 and it came in aid list in 1981. It was upgraded to a High School in 1986 and became aided in 1991.