Neighbours swimming pool pump/filter noise ongoing

Thank you for all the suggestions so far from everyone. Who would have a pool these days?

One of my neighbours had a dug in parapool, never saw them once swim in it, but had the pump running 24/7. Drove me insane. I used to desparetly wish it would die! Then the liner ripped,, probably by their neglected barking lab mix dog. yahoo, pump went off finally. Now it sits, surrounded by waist high grass, with enough water in it to breed mosquitos.

Before going to the trouble of research, approach your neighbours. First off they may be able to try running the pool at different times & reduce the amount it is on. Our own pool filter is in a shed, away from the house , we can't hear it but living rurally no neighbours are near it either. In saying that it is not noisy even at the pool, perhaps that's an indicator that a pump needs a service? If your neighbours are prepared to try soundproofing they may already know how to do that or able to look for solutions. Google may be of some help, poolshops, pump & electrical service people , all would have encountered these types of issues before. Local council may have advice on noise pollution too. Good luck, I hope something helps.

Explosives are good.

Acoustic foam

create your own noise (radio, TV etc) to over-ride it. it only needs to be on low to cover the sound of an external noise.
we have a natural noise that used to drive me insane in the early hours of the morning when I'd had the majority of my sleep, but not ready to get out of bed.
believe it or not, it was the sea which is about 200 metres away. Can't stop the sound of the sea which didn't sound at ALL like what it was. I swore it was a motor running next door, but no, it WAS the sea.
If you go to sleep with a low music noise, it will mute the sound of the motor for the rest of the night.
I'm assuming you're more bothered by it at night than during the day