Answer:
Most strikes are undertaken by labor unions during collective bargaining. The object of collective bargaining is to obtain a contract (an agreement between the union and the company) which may include a no-strike clause or penalizes the union and/or the workers if they walk out while the contract is in force.
It allows the Government of the United States to "make all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution."
Jakarta I believe was announced to being the second largest city in 2015.behing Tokyo-Yokohama.
