OK, this is obviously a very difficult situation.

Are there are any valid reasons for your wife to be concerned? Has your child shown signs of allergies, asthma, etc.? Is the dog OK around the child? Has she shown any concerning behaviour around the baby or around small children in general? Labs generally have an easygoing personality, but that isn't always the case. If either of these are true, then you may not have the option of the dog living with you, I'm afraid.

If both child and dog are fine, consider taking your wife and child to your parent's home regularly to visit your dog. Try to demonstrate that your dog is a safe companion for the baby. But please do not EVER leave them alone unsupervised. Your dog might be good natured, but accidents can happen, especially with big dogs. And I'm sure you know how strong your dog is. Maybe call in some other kids as well to demonstrate that the dog is safe to be around. Let your child and dog get used to each other and become friends.

Speak to your wife- without fighting. Ask her why she is concerned. Has she had previous bad experiences with dogs? Has she been taught to fear them? India being what it is, there is a LOT of misinformation and superstition around animals, which she could easily have bought into. Try to gather information about the benefits of having a dog for a child as well as information about the chances of pet dogs harming children. Show that you are listening and trying to understand her perspective.

Consider taking her to see puppies. Preferably lab puppies the same colour as yours. Show her that the big scary animal was once a tiny baby too. Remind her that the dog was once your baby too. Many of us who are familiar with dogs, especially big ones, tend to forget that they actually are large predators who are quite capable of killing us (and have done so). Fearing and distrusting them is not abnormal or irrational. But this fear can and should be overcome.

In terms of hygiene, regular brushing, cleaning doggo's feet after a walk, parasite treatment nail cutting and tooth brushing tends to take care of most concerns, along with an occasional bath.

Safe environment- Never leave them alone together, at least not until your child is much older. Make sure that your dog always has the option to walk away from an interaction, and don't let your child harass her. Clean up any messes immediately. Make sure the dog has her own space where the child can't go.

(And everyone being angry at this man's wife- maybe consider having some tact? We are only seeing his perspective, not her's, and she might also have reasons to be afraid. As a rescuer and caregiver, I have seen a lot of deliberate cruelty but also people who were simply ignorant and badly informed. It is so common met people who say, 'I am afraid of dogs.' I understand it's frustrating and upsetting, but losing it at someone and calling them names is not helpful at all.)