Dear Sanjay,
I do agree with u that in the Income tax act, there is nothing mentioned about the agreement. However, the right is accrured on a tenant only if there is a tenancy or rent agreement (pls. read Indian Tenancy Acts). In the absence of such an agreeement, the tenant as well as the owner do not have any inherent righs. In the absence of such agreements, the owners try to vacate their tenants by giving them some lump sum amount. this amount is not CG because for the reason that there is no extinguishment of right. When there is no right for the client, how can it be extinguished.
I will tell u a situation in which it is a CG. There is an agreement between teant and owner, as per which tenant can stay in the house for 10 years. After 5 years, the owner asks the tenant to vacate the house. The tenant has the right not to vacate the house. In such case, the owner pays him some lump sum amount for giving up his right. Hence, it amounts to extinguishment of right and CG
Correlating the I.T. act with indian tenancy acts will give a better understanding