No certificate of public convenience and necessity shall be issued, nor shall any taxicab be operated on the streets of the City, until the taxicab company shall have filed with the Mayor a liability insurance policy for each taxicab. The policies shall be subject to approval by the Law Director, shall be kept on file in the office of the Auditor and shall be written by an insurance or liability company authorized to carry on business and to write policies in the State and having a capital and surplus of more than one hundred thousand dollars ($100,000) according to its most recent financial statement. The policy shall indemnify the taxicab company in the sum of at least twelve thousand five hundred dollars ($12,500) for injury or death to one person; twenty-five thousand dollars ($25,000) for injury or death to more than one person and ten thousand dollars ($10,000) for property damage in any one accident through the operation of the taxicab. With the policy shall be deposited a receipt showing premium payments for not less than three months. The policy shall further contain a clause obligating the insurance company to give to the Mayor ten days' notice before the effective date of cancellation of the policy or policies.