China recently built the world’s biggest air purifier in Xian to battle air pollution. Air pollution is a growing concern in many cities including Delhi. The experimental 100-metre-high tower can clean 10 million cubic meters of air each day and reduce PM 2.5 density by 10 to 19 per cent in a 10-square-kilometer area. It traps soot and other noxious particles with a series of air filters and has the purifying efficiency of more than 80 per cent. The cost of the project is $2 million or 14 cr. By following China’s model, Delhi can solve its air pollution problem by installing 3 to 5 such towers spending around70 cr. This seems a feasible solution.