Can Postmaster Gr-i/ii/iii  (or) can any one sign using green  ink?  

Laws in India: Is there any legal or constitutional rule regarding the use of green or red ink on official or government forms/documents?

An important issue came up before the Vajpeyi's Cabinet. Cabinet sent it to the ministry's officials for more remarks and opinions. The file got circulated while some junior officer wrote his comments in Green ink. 

The cabinet secretary was not happy with this so he demanded an explanation. The junior officer in tern asked him to show any rules prohibiting use of green ink. 

Secretary moved the file to minsiter who then refferred it to Ministry of Personnel. That ministry said there is no such rule and Ministry of Science and Technology should be consulted. MTS sent the file to Minsitry of Archieves which said black ink has higher durability compared to others but there is no major difference. 

The cabinet asked Ministry of Defence as to what protocol the defense follows. Turns out that Army, Air Force and Navy all had totally different rules about color of ink. 

After 1 entire year wated on this, and the original decision remaining pending the cabinet eventually simply came up with one random rule. 

This story is the first chapter of Arun Shourie's book "Governance".

As per the available source of information there is no statuary rule in India for usage of green ink in official documents.  School principals, auditors, doctors,  engineers, police stations are widely using green or red ink signs even they are not gazetted. This is useful for  distinguish from clerk to officer marks on file or documents.  But govt. encouraging to use block or thick blue which gives better impression on scanning. Postmasters-i/ii/iii can use green or red for official forms as head of the office to distinguish other signs. In India signature in green is not a status of gazetted. As per Indian legal point of view there is no restriction but it depends on the receiver’s choice.