Yes it is applicable. It is binding the employer in breach of same has to provide damages though the clause cannot be unreasonable.
That depends on clause and work the court interpret in case of serious breaches there are cases where court provide damages though contract act 27 s specified s no agreement on restrain of trade can be made though reasonable restriction for business can be there, see explanation.
Section 27 in The Indian Contract Act, 1872
27. Agreement in restraint of trade, void.—Every agreement by which any one is restrained from exercising a lawful profession, trade or business of any kind, is to that extent void. —Every agreement by which any one is restrained from exercising a lawful profession, trade or business of any kind, is to that extent void." Exception 1.—Saving of agreement not to carry on business of which goodwill is sold.—One who sells the goodwill of a business may agree with the buyer to refrain from carrying on a similar business, within specified local limits, so long as the buyer, or any person deriving title to the goodwill from him, carries on a like business therein, provided that such limits appear to the Court reasonable, regard being had to the nature of the business. 16 [***]