Washington's air turns world's worst after July 4 fireworks extravaganza (X)WASHINGTON: A massive July 4th fireworks display left Washington, DC, briefly recording the worst air quality among major cities worldwide on Sunday, according to global air quality monitoring platform IQAir. The massive 40-minute fireworks display was held as part of America's 250th Independence Day celebrations.The US capital dropped to 26th place on IQAir's global air quality rankings by Sunday evening as pollution levels gradually improved.Code Red air quality alert issuedAs the city officials declared a 'Code Red' air quality alert, authorities urged residents to avoid prolonged outdoor exposure and warned that the air was "unhealthy for seniors, children and people with medical conditions," adding that even h