how much dedication allow

INR. 2500/-

Sec. 16(iii) of the IT Act does not specify any limit. The maximum limit is given under Article 276(2) of the Constitution  of India.

Sec. 16(iii), "a deduction of any sum paid by the assessee on account of a tax on employment within the meaning of clause (2) of article 276 of the Constitution, leviable by or under any law."

Article 276(2) of the Constitution  of India:

"The total amount payable in respect of any one person to the State or to any one municipality, district board, local board or other local authority in the State by way of taxes on professions, trades, callings and employments shall not exceed two thousand and five hundred rupees per annum."