Bombay (Mumbai) Mint has a diamond under the date of the coin (year of issue).

Calcutta mint has no mark under the date of the coin (year of issue).

Hyderabad Mint has a star under the date of the coin (year of issue).

Noida mint has a dot under the year of issue (coin date).

The most important thing about this Noida Mint factory is that it was first started by the Indian finance ministry.