I am a selftaught artist..I do oil on canvas..Mould grow on canvas & damage my paintings...help.?

I live in Kerala, India and its a very rainy place..humidity is also very high.. as soon as my painting gets over, moulds invade them.. i hav tried keeping them in warm places..& keeping them covered, but to no avail.. i rub the mould away, but that takes a good deal of paint with it. i cant even varnish the painting without removing the moulds. but some people dont even advice varnishing. Please help me to protct my paintings from mould