Husband giving false information about his real income

divorce matter given interim monthly payment as maintenance rs 20,000/- per month by court husband gives income tax returns very low saying his income is only rs 30,000/- he is in IT field amd owner of a company whre about 35 people work and deals wiht state govts and also wiht sri lank and bangla desh about the programme he has made he has given income tax returns saysing is salary as Director is only rs 30,000/- pm given income tax returns in support of his income we r sure his income is very high and need to find ways how to prove that