Vet/NGO services needed for neutering street dogs

Please recommend vets or NGOs who can neuter/spay street dogs (and preferably provide them with aftercare for 3-4 days post surgery). We will take care of the expenses, but it would be ideal if the services are discounted. there's a significant rise in new litters of puppies in sec 79, and people are resorting to poisoning them. Disgusting and inhumane behaviour, but I've come to expect nothing less from certain types of humans. Street animals always have the harshest lives, and having neutering drives is absolutely essential to controlling their population and limiting the thankless cycle. Would highly appreciate leads. Thanks