IBM Corp has signed an agreement with the city of Beijing to use advanced weather forecasting and cloud compting technologies to help tackle the Chinese capital's persistent smog. After a series of pollution scares and scandals, China's central government has promised to reverse some of the damage done to the nation's sky, rivers and soil by more than three decades of growth. ButChina has first had to improve data collection, monitoring and forecasting capabilities before it can work on cutting smog and pollution. Beijing city already uses an alerting system based on data from 35 monitoring stations, allowing it to shut schools and factories and cut traffic three days in advance, but residents still complain that not enough is being done.