MUMBAI, Nov. 24 -- The city woke up on Sunday to a thick haze and smog as the air quality steadily worsened in Mumbai. Visibility in several areas, including the coastal road, was low, and the overall air quality index (AQI) stood at 176, with ozone as the primary pollutant. If the air quality remains poor for the next two days, Graded Response Action Plan (GRAP) 4 measures will be implemented in parts of the city, said a civic official. Of the 23 stations across the city that contributed to the poor average AQI, six stations-Mazgaon (294), Deonar (289), Chakala in Andheri (284), Navy Nagar, Colaba (264), Malad West (230) and Powai (206)-were in the 'poor' category. GRAP is an action response formulated by the central government's Commission for Air Quality Management to tackle the issue of air pollution. P3...