The AQI (air quality index) on Thursday hovered around 160 with the conditions being "unhealthy", as the players fought it out on the field. Mumbai: Home team Mumbai's players were on Thursday forced to put on face masks to protect themselves from pollution caused by construction on the first day of their Ranji Trophy tie against Delhi. India and Mumbai batter Sarfaraz Khan, his younger brother Musheer Khan and spinner Himanshu Singh were seen wearing face masks during the third session's play here at the MCA-BKC Ground. While pollution levels have remained high in the city, it is not common among players to wear face masks while playing. For about half-an-hour or so, the three Mumbai players wore face masks while fielding but got rid of them later on.