Pataliputra, the capital of the Mauryan empire, had so impressed Megasthenes, the ambassador of Greek ruler Seleucus I to the court of Chandragupta Maurya, that he called it the world's most beautiful city. The Greek historian - if he could travel through time - would be shocked to move around Patna, the present-day avatar of the ancient city. According to the 2016 Swachh Sarvekshan survey, Patna is the second-dirtiest state capital in the country, after Arunachal Pradesh's Itanagar. Poor infrastructure and bad air quality have added to the Bihar capital's woes. Now, the Patna High Court has asked the authorities concerned to file a detailed report on what they are doing to prevent air pollution in the city.