Saluting to other flag

It is not wrong or unlawful to salute some other nation’s flag as there is no mention against it in the Flag code of India, 2002. The individuals have complete freedom to do so.
The code is a set of laws, practices and conventions that apply to the display of the national flag of India. Flag Code of India, 2002, has been divided into three parts. Part I of the code contains a general descripttion of the national flag. Part II of the code is devoted to the display of the national flag by members of public, private organizations, educational institutions, etc. Part III of the code relates to display of the national flag by union and state governments and their organizations and agencies. The Flag Code of India, 2002, took effect from 26 January 2002 and superseded the “Flag Code-India” as it existed earlier.
However according to section VI of the code it is mandatory during the ceremony of hoisting or lowering the Flag or when the Flag is passing in a parade or in a review, all persons present should face the Flag and stand at attention.

The flag code of India, 2002 – https://www.mha.gov.in/sites/default/files/flagcodeofindia_070214.pdf

Best Regards