There are two possible reasons.
Firstly, the Token Generation Event where $SWEAT was first made available to the public was only available to Sweatcoin app users. The app is currently available in these countries; but stay tuned, because we're rolling out the app globally.
Secondly, there were simply some areas which we could not launch in at the time, because of regulations related to crypto.
Countries where $SWEAT is currently not available:
Albania
Belarus
Cambodia
China
Crimea
Cuba
Iran
Mauritius
Myanmar
Nicaragua
North Korea
Palestinian Territories
Panama
Russia
Syria
Yemen