Thick smog cloaked Delhi Wednesday as the national capital’s winter pollution worsened a week ahead of the Diwali festival, when firecrackers typically intensify the haze. (Bloomberg) -- Thick smog cloaked Delhi Wednesday as the national capital’s winter pollution worsened a week ahead of the Diwali festival, when firecrackers typically intensify the haze.The citywide air quality index reached 379 at 10 a.m.