Bengaluru: Three sanitation workers died of asphyxiation while cleaning a manhole on Friday in the district headquarters town of Ramanagara, about 50 km from here.“The three sanitation workers from Bengaluru had entered a manhole to clean it and died of asphyxiation. More details are awaited,” the Ramanagara superintendent of police S. Girish told PTI.Also read: #Grit: On World Toilet Day, a Look at The Wire’s Coverage of SanitationAccording to police, six people were brought from Kamala Nagar in Bengaluru by a contractor to clean the choked sewerage.As one of them entered, he died of asphyxiation. The other two met the same fate in a bid to save their colleague.The police were in search of the contractor who had brought them from Bengaluru.