There are not many international flights to intended destination and the cost is high. Is it ok with the rules if I land in another city and book a domestic flight separately.
Edit I am travelling from Canada to India. My wife and I have Indian passports and my kid has Canadian passport with Indian travel visa
India has absolutely no restrictions on which ports of entry an Indian citizen, PIO/OCI holder, or visa holder can enter the country (except for Pakistani citizens, who can only enter via MAA, DEL or BOM).
In the past, India did issue restricted visas to people of certain nationalities, which could only be used to enter India via a single port of entry. This restriction was removed a few years ago, and now visas can be used to enter India at almost any port of entry, even if they have such a restriction printed on them.
Note that there are restrictions on entry ports for e-visa holders. With an e-visa you can only enter via 28 international airports and five seaports. This covers almost every airport in India that you might think about flying through, so it should not be an issue for you, but you should double check that your intended airport of entry is on the list if you are using an e-visa.
From a rules point of view, I think you are okay. You can land at any port, go through immigration and enter your final destination address in the immigration form.
I agree with @Willeke, when you give the final destination on sites like expedia/kayak, they show the domestic leg as part of the same journey. I would recommend you do this for two reasons
International flights usually have better baggage allowances and they will let you carry the same number of bags on a connected domestic flight (as it is part of a single reservation)
If for some reason, the international flight is delayed, you will get better support (like being placed on the next available flight) if it is part of the same reservation. A separate domestic ticket will not have the same benefits.
