Not required, but it might be required during the time of counselling and admission.

Hi! Gap certificate is not required to write NEET but during admission to colleges  certain states require you to produce a Gap certificate while certain states don't. It's a very simple procedure and you can get it done in 1-2 days.

Generally they do not ask. But the requirements of document for different colleges is different. It's better to have one. Get all ur documents ready, photo copy them, get them attested in advance