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Dozens of people attending the Bola Preta Carnival parade in central Rio de Janeiro on Saturday (February 09) had to receive medical attention after fainting due to the heat and the sheer size of the celebration.

As the carnival was in the final stages, the streets became clogged with people trying to leave but with nowhere to move to.

City officials estimate that almost two million people came down to central Rio on Saturday morning to take part in the festivities.

The chaos started when two police cars drove through a crowded area. With nowhere to turn and under 30 degree heat, people panicked.

Revellers could be seen hanging from lamp posts, jumping through fences, and even getting on top of the police cars to find some breathing room.

All the injured received medical attention on the spot, but city officials opened an inquiry to work out ways to avoid the incident from happening again.

The Bola Preta parade is famous for drawing some of Carnival's biggest crowds. It started in 1918 and stands today as one of the oldest and most popular carnival street parties in Rio.