498a dv case & crpc 125

When you have mutually agreed to pay 20k per month there is not effect whether you disclose your income or not.

That is what I had initially thought. However, the judge in DV case has suddenly turned hostile and there is a risk of him increasing this maintenance amount by asking me to produce my ITR and bank details. 

Is there any pending application of enhancement of maintenance?

Income tax return is personal confidentail matter and it is not easy to gather the information relating to IT. Since matter has already been settled in mediation then there is nothing to worry.

No, but the opposite party has also become agressive. They submitted in DV case application to get court order for disclosure my income details. 

Details like case and court orderes are required to be examined to give any advise.

If you want to conceal income and ready to face the ire of the IT department, you may do as your wishes. Otherwise, filing of IT Return is mandatory for you if you have taxable income, whereas 498a, DV and 125 cases are your family problems, which do not provide you any immunity from IT Laws.