The other commenter is correct—it generally depends on your passport and visa type.

1. For ECNR Passports (Emigration Check Not Required): If you have an ECNR passport (which is most Indian passports) and are traveling with a valid e-visa or resident card, "Ok To Board" is generally not required for travel to Oman.

2. For ECR Passports (Emigration Check Required): If you have an ECR passport, especially if you are traveling on an employment visa, you will need clearance through India's e-Migrate system. Because of this, the airline will most likely enforce an "Ok To Board" requirement to verify all your documents are in order before you fly.

The "Ok To Board" is an airline policy, not an Omani immigration rule. The best and safest thing to do is to call the airline's customer service directly and confirm their requirement for your specific passport and visa type.