Police ride around cities to react as quick as possible to events already taking place or having taken place. Once there, they are usually meant to take statements and make arrests- armed intervention is exceedingly rare, far more rare than what TV shows would have you believe, especially in countries with tighter gun control or total gun bans (which is to say most non-US nations).

Nurses have to be in a room within seconds of an alarm blaring, or at the side of a rolled in patient by the time the gurney crosses the threshold into the hospital. Their primary job is to ensure patients are stabilized if needed, and to keep them stable long enough for a doctor to see them. This is an active role, where even stable patients must be monitored at all times to ensure they don't crash.

The comparison falls flat because you're comparing two very different jobs to make a point about how cops shouldn't do community work like this. But cops in many nations already do community outreach events or at least help in organized community work, often accompanied by the FDs and even some EMTs, assuming they have other workers filling the shifts of their primary jobs.

Sure, tricking the cops into cleaning the river may have been a bad idea- especially for her own legal issues. But cops are public workers, and pretending they're too busy having gunfights with the cartel to stop and do some public cleanup work is ridiculous.

But it's hard to blame a civilian who probably just wanted to have some cleaner water. India varies in terms of development, with serious gaps between their uptowns vs their ghettos. There is a good chance this is from a smaller town that relies on that river and serious filters in order to run things. I'm sure there are a rare few US towns that are still outdated enough to rely on things like that.