Mahatma Gandhi returned to India from South Africa in January 1915. He initially lived in Kochrab Ashram before moving to the Sabarmati Ashram in 1917. However, the establishment of the ashram at the Sabarmati site is generally considered to be in 1915, when he moved from Ahmedabad to the banks of the Sabarmati river. Some sources might refer to the formal inauguration at the current site in 1917. Given the options, 1915 is the most appropriate starting point for his presence at Sabarmati, even if the permanent structure was completed later.