Section 40: Burden of obligation imposing restriction on use of land, or of obligation annexed to ownership but not amounting to interest or easement.

Where, for the more beneficial enjoyment of his own immoveable property, a third person has, independently of any interest in the immoveable property of another or of any easement thereon, a right to restrain the enjoyment [in a particular manner of the latter property], or

Or of obligation annexed to ownership but not amounting to interest or easement.-- Where a third person is entitled to the benefit of an obligation arising out of contract and annexed to the ownership of immoveable property, but not amounting to an interest therein or easement thereon,

such right or obligation may be enforced against a transferee with notice thereof or a gratuitous transferee of the property affected thereby, but not against a transferee for consideration and without notice of the right or obligation, nor against such property in his hands.

Illustration

A contracts to sell Sultanpur to B. While the contract is still in force he sells Sultanpur to C, who has notice of the contract. B may enforce the contract against C to the same extent as against A.