Increase in average yield due to the improvement at the expense of holders not to be taken into account

Increase in average yield due to the improvement at the expense of holders not to be taken into account.— If during 30 years immediately preceding the date on which the settlement for the time being in force expires, any improvements have been effected in any land by or at the expense of the holder thereof, the increase in the average yield of crops of such land due to the said improvements shall not be taken into account in fixing the revised assessment thereof.