Why does Manhattan smell in the summer?

NEW YORK -- You can't deny the allure of Manhattan in the summertime. But on a hot day, there's something beyond the thermostat that increases: the smell.

"I don't think of New York as stinky, but when it hits you, it hits hard," resident Pamela Vilorio said.

There are many reasons why it's hard to escape the stench, according to AccuWeather. New York City has the highest population density in the country. According to the U.S. Census, it's about 27,000 people per square mile, and that much body odor can cause problems.

With that many people also comes a lot of garbage. When the heat and humidity get more intense in the summer, so does the smell.

The city is usually warmer because of pollution, which causes a greenhouse effect and allows bacteria to grow faster and also contributes to the smell.