N.Y. Second Class Cities Law § 79

§ 79. Contracts and expenditures prohibited. No officer, board, or\ndepartment shall, during any fiscal year, expend or contract to be\nexpended any money or incur any liability, or enter into any contract\nwhich, by its terms, involves the expenditure of money for any of the\npurposes for which provision is made in the annual estimate in excess of\nthe amounts appropriated in said estimate, as adopted by the common\ncouncil, for such officer, board, department or purpose, for such fiscal\nyear. Any contract, verbal or written, made in violation of this section\nshall be null and void as to the city, and no moneys belonging to the\ncity shall be paid thereon, provided, however, that nothing herein\ncontained shall prevent the making of contracts for light or water, the\ncollection and disposal or the disposal of garbage, the collection and\nremoval of rubbish and ashes, the cleaning of streets, or the sprinkling\nof streets or public places by railway cars, for periods exceeding one\nyear.\n Nothing herein contained, however, shall be held to prohibit the\nexpenditure of such sums as may be made available, pursuant to section\nseventy-six of this chapter or section 29.00 of the local finance law.\n