When the rent of a tenant has been fixed by a Settlement-officer under section 63, or where a tenant has agreed to pay an enhanced rent for his holding under section 65, or when a tenant is holding at a rent fixed as fair and equitable under section 66 or section 78, or when a rent has been agreed upon by contract or consent between the landlord and his tenant in respect of any holding, or when an order under section 66 to eject a tenant from his holding has become void from failure of the landlord to deposit the amount of compensation (if any) determined as due to the tenant under section 32, no notice of enhancement under section 64 shall be served on such tenant in respect of such holding, nor shall any further enhancement, by contract or consent or otherwise, in respect of such holding be permissible, for a period of seven years from the date on which the settlement made by the Settlement-officer took effect, or from the date of such fixation, agreement, contract or consent, or from the date of such order for ejectment becoming void, as the case may be :
Provided that, where a tenant is holding land under a special contract with his landlord at a favourable rent for a term of years in consideration of temporary deterioration, or of the labour or expense involved in the reclamation by such tenant of the land from waste, nothing in this section shall be constructed to prevent a fair rent being fixed or agreed upon after the expiration of the term of such contract.