I am not sure where about in India he collected them. They are roughly the size of a postcard https://imgur.com/a/07d0FSV
The second one says something like "This is a great opportunity for Asians ("inhabitants of Asia") to drive the English (sic) away from Asia". 4th one says something like - "As a slave of the English" and "The rule of famine and death" (left) and "After becoming independent" , "happiness and peace will rule" (right). Not sure if this is something you are looking for ? I have seen something like this at the National Museum of Singapore.
Edits added. The languages are Hindi and Bengali which would make sense since the Japanese advanced mainly from the Eastern part of the country.