India, Dec. 15 -- The national Capital saw the toughest anti-pollution measures - Graded Action Response Plan (GRAP) Stage IV - kick in on Saturday after the air quality index (AQI) reached the "severe" category. Just a few hours earlier, GRAP III, the penultimate level of curbs, had been announced. With GRAP IV, serious restrictions on vehicle movement and construction are in place and classes have been shifted to online from the physical mode. The Commission for Air Quality Management in NCR and Adjoining Areas (CAQM) has also said that states with districts bordering the national Capital, which are also affected, may consider allowing 50% of employees to work from home. Given AQI moved from "very poor" to "severe" in a matter of hours, it is highly likely that the deterioration wasn't entirely unforeseeable. This raises the question if the response could have been better. The health effects of "severe" AQI are serious - pollution at such levels affects not only those with pre-existing respiratory conditions, but also those with healthy lungs, as medical experts have reported for a while now. An optimal response to pollution will require improved predictive systems which enable measures to kick in well in advance of pollutant concentrations reaching unbreathable levels. This calls for not just robust real-time data to establish trends and extrapolate as needed, it also perhaps calls for relooking at our air quality standards. While every country must take into account its own realities while setting these standards, it will pay off in the long run to work towards adhering to aspirational standards, such as the World Health Organization's....