Crying in a hospital bed with a nebuliser mask on his tiny face, one-month-old Ayansh Tiwari has a thick, hacking cough. His doctors blame the acrid air that blights New Delhi every year. The emergency room of the government-run Chacha Nehru Bal Chikitsalaya hospital in the Indian capital is crowded with children struggling to breathe -- many with asthma and pneumonia, which spike as air pollution peaks each winter in the city of 30 million people. Delhi regularly ranks among the most polluted major cities on the planet, with a mixture of factory and vehicle emissions exacerbated by seasonal agricultural fires. IMAGES AND SOUNDBITES ARRANGED IN SEQUENCES