1) you would be eligible for OBC NL certifcate

2) your parents income is considered and not your income for determining your NL status

3) in your case your father was ateacher in govt and mother housewife and you would be eligible for OBC NL status

4) salary income is not applicable for Govt servants.

The salary of government servant is not considered for deciding creamy layer, however the status of the government servant is a deciding factor for creamy layer. Sons and daughters of direct Class 1 or Grade A are under Creamy Layer

Certificate & Self-declaration Format for OBC(Non-Creamy Layer)

Central List of OBC

Revision of income criteria-The limit of annual income of Rs. 4.50 lakhs has been raised to Rs. 6.00 lakhs for determining the creamy layer among Other Backword Classes (OBCs) candidates in the centrally funded technical education institutes.

If you fall under OBC-NC (Other Backward Classes-Non Creamy Layer) category then you may apply under OBC-NC category while applying Online/Offline,even though if you have declared your birth category as GN (General) while applying for GATE. However you have to produce the OBC-NC certificate at the time of Written Test/Interview.

NCL is purely based on your parent’s income.