How many meters can the airport visibility reach the take-off standard?

According to the East China Air Traffic Control Bureau, at present, Hongqiao and Pudong airports only have the second level of blind drop. Although it is at the advanced level in China, its limitations are: the visibility is above 500 meters before the plane can take off; The visibility is above 800 meters before the plane can land. In order to enhance the "anti-fog" ability of aircraft taking off and landing, Pudong Airport will put into use the internationally advanced third-class blind landing system at the end of this year. By then, even if the visibility is less than 200 meters in foggy and thunderstorm weather, the plane can still take off and land.