Dog shelter

I've done something similar in Africa. I've also rehabilitated stray and feral dogs and rehomed them for the RSPCA. The best way to catch them is to first entice them with food and then befriend them, this can take a week or two but dogs usually tend to scavenge around the same places so try that first. Second option is use food to entice then use a dog catcher loop to catch them and quickly contain them, work with them once you have them caught. Dogs want to trust people. You might not like the loop but it is a safe way to catch potentially aggressive dogs quickly so that you can take them somewhere safe to work with them. Sometimes you need to trap one or two but the majority will sell their puppy souls for a decent meal. Just remember that your aim is to remove them from the dangerous streets as fast and humanely as possible.

Be careful of administering pre-surgery sedatives to dogs with a possible pit/bull-dog ancestor in the mix as it can remove their inhibitions and lead to bites. Don't be afraid to use a soft muzzle if you must. It can be terrible for a dog to bite someone out of fear when they've just started to trust you. Better for them and you if that kind of incident can be avoided completely.

Good luck! Feel free to pm me if you have any further questions.

This is really such a noble gesture. Every animal deserves a chance at a good life isn't it? Wishing you all the best and that you find the help and support you need to put these animals in a safe environment.