It shall be unlawful for any seller and for any driver, or handler, or for any agent or employee, of any seller to deliver or to transport for delivery, to any purchaser in a residential district any commodity at any time on Sunday or between the hours of 6:30 p.m. and 6:00 a.m. on other days; but in case of emergency, the police chief may issue a permit for transportation and delivery on Sunday or between the hours above named on other days.