No, the US has never done any blocking in the GPS system. The article refers to a request by India for access to the military GPS signal and military equipment, which was not granted.
The US, as well as virtually all other technological powers, does have the capability to jam GPS signals using ground, sea, or air-based jamming platforms but those are not part of the GPS system.
The US, as well as virtually all other technological powers, does have the capability to jam GPS signals using ground, sea, or air-based jamming platforms but those are not part of the GPS system.