Mumbai: Shiv Sena-UBT leader Aaditya Thackeray on Sunday urged the Brihanmumbai Municipal Corporation (BMC) to impose an immediate week-long halt on private construction activities, citing worsening air quality and what he described as Mumbai being “engulfed in terrible smog”. In a strongly worded letter addressed to Municipal Commissioner Bhushan Gagrani, Thackeray raised concerns over deteriorating.