Mr Sunil,
Your relinquishment of right in past is immaterial, as any gift from siblings of your parents is tax free in your hand.
Coming to pointed reply, it appears that your uncle is gifting you your share in the sale proceeds and not the actual property (As he is selling the property). Hence it is a simple case of gift of money.
No capital gains are leviable in the transfers in the nature of gift. In your case as the gift itself is in form of money, the same does not fall under the ambit of capital gains at all.
Lastly, about wealth tax, if you do not keep the gift received in form of cash, jewellery, car, urban plot or other specified items includible in wealth, atleast this amount will not be included in taxable wealth.
Hope it resolves your query. So enjoy the gift without any worries.