A number of train passengers fell ill after complaining about a strange smell and were taken to hospital in Tokyo.
Japanese police, along with the fire department officials, are investigating the reports to find out the cause of such a smell.
The Tokyo Metropolitan Police Department said nine passengers, who were affected by the strange smell, had been travelling on the Seibu Shinjuku Line at Tokyo's Takadanobaba Station.
Passengers said they experienced a smell similar to that of paint thinner, Xinhua reported.