On the photo you can see some of the crowd last new year. When all that mass starts to press on you...

37 people were trampled to death in Shanghai at new year.  Somebody slipped at stairs with lots of people, there was a panic and so it happened. 47 were injured, 13 dangerously.

Tight crowds can become dangerous. One year ago I was in Helsinki where New Year is celebrated in a square in front of the cathedral. Because of the warm weather  the place was packed and when the ceremony was over, people turned to go to see more fireworks. Even on the edge of the square where I was, there were many rows of people in front of me. They could not go fast and the pressure from the rear, where most of them were was very strong. I felt that if someone happened to fall, it could have been dangerous and shouted to people to stop pushing.