What is the year of the Film? This question is often asked but it may surprise you to know that it has many answers. The most definite answer is the year mentioned on the censor certificate, which is published in the Gazette. This used to be hard to find. However, now the year and the whole censor information of Hindi Films from 1931 to 2010 is available on the website

http://hamraaz.org/hfgk

This information has also been published in a book form, both in English and Hindi:

Censor Certificate Information of Hindi Talkies (1931-2010), by Har Mandir Singh 'Hamraaz' and Prof Surjit Singh (2021 English)
Censor Certificate Information of Hindi Talkies (1931-2010), by Har Mandir Singh 'Hamraaz' and Prof Surjit Singh (2022 Hindi)
Then one also has the year or more properly the date of the Film release. There is no official publication for this information. Also, this information changes from city to city as Films having limited number of prints, cannot be released everywhere at once. Finding this information requires much more work. One can find it in the magazine reviews, magazine and newspaper ads, and, sometimes in the trade publications. All these sources are hard to come by.
Luckily a few Indian newspapers are available on the internet, for example Indian Express, madras Edition. Recently, SS and two of his co-workers published a book on the Films running in the Madras theatres,

Films Showing in Madras Theatres (1941-1947), by MV Surender, N Ramaswamy and Prof Surjit Singh (2021)
In the book at hand, we present information about the talkies running in Bombay in 1941. We plan to cover the years 1931-1950 at least. This information is based on the Bombay Chronicle newspaper available on the Internet Archive website.
It is fascinating to follow the life of many Films, some run for a long time, some only a few weeks, some move to other theatres. We found this information to be enjoyable to work with and fascinating.
We hope that our readers will also enjoy this nostalgia-inspiring work.