NANJING, April 14 (Xinhua) -- Nanjing, capital of east China's Jiangsu Province, launched an online forecast based on monitoring the flying catkins from blossoming oriental plane trees, as the cotton-like seed clusters cause widespread spring headaches from allergic reactions such as rhinitis, asthma and dermatitis.

The catkins flower in April and May in the city. There are over 90,000 of the streetside plane trees in the city's downtown, which add beauty to the urban landscape but generate huge amounts of choking catkins flying in the spring air.

Local authorities said Friday that the catkin forecast based on the monitoring of 58 downtown roads and streets will continue until June 10.

The forecast is updated each hour and provides the density of catkins and its trajectory over a three-hour period, using a color block diagram, a line graph and a thermodynamic chart.

The system was developed by the Nanjing Landscape and Forestry Bureau together with the Jiangsu Provincial Meteorological Service Center. People can check the catkin forecast on the bureau's official website and its social media accounts such as Weibo and Wechat to avoid the annoying encounter of the flying clusters.

Yuan Bixin, an official from the bureau, said currently, there is no effective way to harness catkins. The bureau has tried to reduce the number of seeds and flowers from plane trees by way of grafting, injecting growth inhibitors, and washing the streets with high-pressure water guns.

"The efforts have reduced the number of catkins by half, but can't completely solve the problem," he said.