Tokyo (Japan), Sep 12 (ANI): Tokyo has the highest density of population in Japan. The countermeasure against disaster is the most important task for the Tokyo Metropolitan Government. Recently, the countermeasure against typhoon or squall is being built to keep the city safe from natural disasters. Tokyo Metropolitan Government continuously monitors the situation in Tokyo and the safety of the city is its top priority. The camera is set at 47 points of the river and the situation of the river is observed 24 hours. The government monitors and analyses data of rain gauge, water gauge and dispatches appropriate information to the citizens. When the water level reaches to dangerous mark, the information is automatically dispatched to the water disaster prevention room. In that room, staff can watch the situation of the river through an observation camera. The government's water disaster prevention general information system can provide information both to the citizens and foreign tourists on the internet in various foreign languages. People can check the real-time image of the river and water-level using the location of PCs and smartphones. Tokyo will host the 2020 Olympics. Japan has a history of being a victim of natural disasters. The focus on disaster prevention technologies of Tokyo is has increased owing to the attention the city will get from all over the world during the Olympics.