When insurance is required under any provisions of this code, except under section 2-5-303 of this code, the insured shall be obligated to indemnify the city for any damage or injury caused to the city as a result of the conduct or activity requiring insurance. The form of indemnification shall conform to the rules and regulations issued pursuant to section 3-4-5 of this chapter. (1962 Code §§ 2-6.405, 5-8, 7-4, 9-3.1200 et seq.)