The iconic Howrah Bridge in Kolkata will be closed to traffic for five hours from 11.30 pm today for a "comprehensive health check-up" for the first time in 36 years, according to Syama Prasad Mookerjee Port. Approximately 100,000 vehicles and 1,50,000 pedestrians cross the 81-year-old steel bridge, also known as Rabindra Setu, daily. RITES Ltd will carry out the audit.