What is the procedure for Irrigation works contractor

Hello Everyone,

One person is doing contract works for irrigation department.Actually, he is a small contractor and he is getting contract works twice in a year and the value of the contracts is not more than 20Lakhs. So, he is filling nil returns until he receives works from irrigation department. Six months back he received one contract work and the value of the work is 8 lakhs. He has finished his work but still the department not made payment to him and normally he is filling nil returns.

please suggest anyone that he is doing correct procedure or not.
What is the procedure for Irrigation works contractors.