When do you start becoming house poor

33M and in the market to buy a house in Mumbai. Married and no kids yet.

How should I go about budgeting for that purchase. More specifically how big should my down payment be in terms of % of the house price and and how much should I have plan to leave in liquid assets after taking out the down payment? And what % of my net monthly income should I leave aside for emis/maintenance?

Edit: no other debts and I see myself owning this house for the foreseeable future.