The Air Quality Index in the city on Sunday was 138, placing it in the ‘moderate’ category. The Chennai Open singles final between top seed Janice Tjen and Magda Linette was postponed to Monday morning after smog from Diwali fireworks engulfed the SDAT Tennis Stadium on Sunday evening.. Diwali fireworks added to Chennai's air quality woes as rain further disrupted proceedings, forcing the women's singles final to Monday.