23. General prohibition of strikes and lock- outs.- No workman who is employed in any industrial establishment shall go on strike in breach of contract and no employer of any such workman shall declare a lock- out--
during the pendency of conciliation proceedings before a Board and seven days after the conclusion of such proceedings;
during the pendency of proceedings before 1[ a Labour Court, Tribunal or National Tribunal] and two months after the conclusion of such proceedings; 2[
3[ during the pendency of arbitration proceedings before an arbitrator and two months after the conclusion of such proceedings, where a notification has been issued under sub- section (3A) of section 10A; or]
during any period in which a settlement or award is in operation, in respect of any of the matters covered by the settlement or award.