Under Section 1(2) of the Hindu Marriage Act, 1955, what is the territorial extent of the Act?

Section 1(2) of the Hindu Marriage Act, 1955 extends the Act to the whole of India, and it also applies to Hindus domiciled in the territories to which it extends who are outside those territories. The former exclusion of the State of Jammu and Kashmir ended when the Act was made applicable to the Union territories of Jammu and Kashmir and Ladakh under the Jammu and Kashmir Reorganisation Act, 2019, with effect from 31 October 2019.

The application of the Act to persons (Hindus, Buddhists, Jains and Sikhs, and others who are not Muslims, Christians, Parsis or Jews) is a separate matter dealt with in section 2; the question asks about territorial extent.