Ask HN: Why Don't People Wear Masks For Pollution in Delhi?

Yesterday Delhi's ambient concentrations of fine particulate matter (PM2.5) breached 800 micrograms/cubic meter according to real time data collected by the Delhi Pollution Control Committee. As far as I am aware, no schools were closed, and I don't see anyone wearing masks. In Shanghai the public has been much more responsive and has voiced concerns regarding poor air quality. For reference check out the wsj articles below (if you google search the titles you can bypass the login requirement in order to read the articles). Shanghai https://www.google.com/search?q=Shanghai+Hit+by+Heavy+Air+Pollution Delhi https://www.google.com/search?q=Delhi%27s+dangerous+air+pollution+problem Steps to Reduce Your Exposure (US Embassy - Beijing) http://beijing.usembassy-china.org.cn/20130201-pm25-steps.html