Excerpt:
Seven die while cleaning hotel sewer in India's Gujarat
...
Their bodies have been recovered in the village of Fartikui, and the hotel owner has been charged over the deaths.
...
According to police, the incident began after one sanitary worker entered the septic tank. When he did not return from the tank or respond to calls, his three colleagues went in to find him.
Later, when none of the four had come out, three hotel staff went in to help them, but they too fell unconscious and died.
https://www.bbc.com/news/world-asia-india-48648769
Apparently known as a dangerous profession there, related:
India's sewer workers risking their lives
By Yogita Limaye Mumbai correspondent, BBC News
https://www.bbc.com/news/business-35958730
