trading income

Technically you have given a false affidavit. But the seriousness will depend on for what purpose you gave the affidavit and the seriousness of the consequences of your having an income of Rs.1700/-

There are two points in this case. 1. By filing false affidavit and suppressing facts whether you have committed perjury. 2. Since you had income whether you are eligible for maintenance from your wife. 1. According to me Rs.1700/- is a trivial amounts and any charge of perjury can be condoned. 2. In order to  deny maintenance from wife (or any other person on whom one can have a claim) income in a particular year is not sufficient. One should have regular income year after year. I do not imply here that you have a claim if you did not have other sources of income. That is an issue to be decided by the court.