Reading list: Does GST apply to under-construction flats?
Yes, GST applies to most under-construction flats because the property is considered a service until the building is fully completed. For people buying a flat in Ahmedabad, GST is charged on the portion of the payment made before the project receives the completion certificate. The standard GST rate for under-construction residential units is usually 5% (without ITC) for normal housing and 1% for affordable housing. Once the project is completed, no GST is applicable.
Conclusion:
If you are buying a flat in Ahmedabad, check the project’s construction status—because GST is only payable on under-construction units, not on ready-to-move homes.
https://www.laxmigroup.co/articles/hidden-costs-to-watch-out-for-when-buying-a-flat-in-ahmedabad/