The Celebration of the Rights of the River Cam is an upbeat midsummer event on Jesus Green, now in its fourth year, which brings together people concerned about the now-endangered river which had sewage dumped into it for 4,400 hours in 2023. The river that has been enjoyed by swimmers including Lord Byron, Charles Darwin and Virginia Woolf is looking increasingly forlorn as the pollution from sewage joins phosphate and nitrate discharges from farmland. Dangerous levels of the E coli bacteria have been found in the River Cam just weeks after it was declared an official bathing site for wild sw…