The fixed money rent of the bighori, determined under section 151, of an occupancy, an exproprietary or a hereditary tenant, shall be liable to enhancement on one or more of the following grounds:--
         (a) that the rent payable by the tenant is substantially less than the rent calculated at the sanctioned rates appropriate to him; or
         (b) that the productive power of the land held by the tenant has increased by an improvement effected by, or at the expense of, the land holder, other than a work in respect of which irrigation dues are payable under section 87 or which is carried out under the scheme sanctioned by the Central Government under section 5 of the Delhi and Ajmer-Merwars Land Development Act, 1948 (LXVI of 1948); or
         (c) in case of fixed money rent, that the area of the holding has been increased by alluvion.