is it capital gain or income ?

Respected Sir / Madame, sub : is it capital gain or income ? Essential Background : my name is prashant shirodkar ( birth date - 26 august 1955 ) sometime around 1952, my father become TENANT in a small bunglow, at the western suburb, mumbai. that was a 1 room kitchen space. i am sheath & sheen at this place. my father expired in 1996 and our landlord put my name on the rent receipts. after the demise of our landlord, in the year 2005, `the property' changed hand and the new landlord who is a builder, proposed to development and offered me same space (330 sq ft ) in the proposed new building. by a simple agreement, ( the document was not registered ) i vacated, and after the completion of construction, occupied my 1 room kitchen space ( self contained, now ) again. within a year or two, my landlord acquired 1more property, which is on the adjoining plot. now he has proposed to develop it, but with amalgamation. for this, he needed my consent and / or registered agreement with me. my lawyer / advocate asked me to measure my space, and we found it is less than what was agreed. so my lawyer / advocate created, a new Lease Deed, for 9 years & 9 months on monthly rental, mentioning every detail, and some compensation in `cash'. my landlord agreed and paid me that amount by depositing 3 cheques in my bank account ( totaling, say Rs 400,000/- ) i paid Government's Stamp Duty & Registration charges by cheque from my account. my question is : is this amount considered as Capital Gains or Other Income ( Taxable ) ? in case of Capital Gains, If, i receive Income Tax Department's Notice in near future, how to prove that this is Capital Gains ? in case of Other Income, I am ready to pay Income Tax. Please advice me in detail...