Neeche diye gye ye wo groups hain jo apr month main kaam nahi kar rahe or jinka business kam hoya hain apr month main compare to march month
It is below that group which have not done work in the month of April, and whose business has been reduced in the month of April, in comparing to march
@preetG:
First of all, writing all the question again leaves the post clumsy and spacious. Put those parts only which are required or you are putting an emphasis on.
Coming to your sentence:
1. It is below that group which have not done…
rather “group of those (persons) who have not done…”
2. in comparing to march
say “in comparison to (Month of) March” or what anuj.k.mishra suggested.