Honestly, the trick to keeping an urban trash can from turning into a summer smell factory is to fight moisture and organic waste before they sit. In a city, bins often get hit with food scraps, liquid leftovers, and hot alley air, so a little routine makes a big difference.
First, empty it more often than you think, especially in July and August. Use a sturdy liner bag, and tie it closed before it fills up. Keep food scraps in a small sealed container or compost bag rather than loose in the bin. Never pour liquids, soup, or milk into the can; that is what makes the bottom sour.
Give the can a quick rinse and scrub once a week with dish soap and warm water, then let it dry completely in the sun before putting a new bag in. If it is really smelly, wipe it down with white vinegar. Sprinkle baking soda in the bottom of the bag or bin to absorb odor and moisture. Keep the lid closed so rain, flies, and neighborhood cats stay out, but let the bin breathe for a few minutes after cleaning. In summer, place it in the shade if possible, and make sure pickup day is on your calendar.
If the smell lingers, check for cracks or a buildup of liquid under the bag; that is usually the culprit. A clean, dry, well-lined bin with regular pickup is honestly 90% of the battle.