28. Every tenant holding under an unexpired lease, or having a right of occupancy, who is in occupation of any land at the time when any stoppage or diminution of the supply in respect of which compensation is allowed under section 11 takes place, may claim an abatement of the rent previously payable by him for the said land, on the ground that the interruption reduces the value of the holding: Provided that no part of the said compensation shall have been received by the said tenant in respect of such reduction in the value of his holding.