There are situations when it is mandatory to get income tax clearance certificate. For example
when one leaves India permanently or when a non-resident who want to return back to his home country after completing business or who was under employment in India
The process of getting income tax clearance certificate is regulated by Section 230 read with relevant rules.
If you are an Indian and want to leave the country
Then in such scenario you need to submit Form 30C Chief Commissioner of Income Tax or the concerned authority
Once the application is approved certificate will be granted in Form 33
If you are a person who is not domiciled in India, who has come to India in connection with business, profession or employment and who has income derived from any source in India
Then in such scenario you need to submit Form 31 to the Employer or to the Person from whom you have received income. Then on the basis of this information, employer or the person will submit details in Form 30A to Chief Commissioner of Income Tax or the Director General of Income Tax. Once the application is approved certificate will be granted in Form 30B