Latex paint is a water-based paint that is similar to acrylic paint. The main difference between acrylic and latex paint is acrylic paint is chemical-based compared to water-based latex. Although latex paint is water-based it is still comprised of acrylics and vinyl which both have negative environmental impacts.
There are several ways to dispose of your leftover paint however to help the environment please consider a few alternatives before disposing of the paint.
Saving the leftover paint: Depending on the amount you have leftover, it might be worth considering saving the leftover paint either in the tin it came in or in a smaller tin/plastic pot. As long as it's sealed the paint will last for further touch-ups in the future.
Giving the paint away: If you have too much paint to save for later touch-ups it might be worth looking for someone that will be able to use it. Try asking around friends, family, and neighbors to see if anyone would want the paint, and if not you can also ask local schools or facilities. You can also look into websites such as freecycle and gumtree to see if anyone would want it for free around your area.
If you want to dispose of latex paint it's worth understanding that it can't be put in your regular bin in its liquid form. This in most countries is considered illegal and you should first try to attempt to dry the paint.
Depending on the amount of paint left you can either leave the lid off of the tin if the tin has less than 1 inch of paint left in it. Leave the tin in a well-ventilated area for about a week to ensure the paint properly drys up. If you have a larger amount of paint left, you can either pour sawdust, cat litter, or newspaper into the remaining paint to help it dry faster and harden. If this doesn't work for you, you can also pour the paint into separate cardboard boxes and allow it to dry before disposing of.
Please make sure to NOT pour the paint down your drains as this can cause local blockages which will lead to issues in the future. Also, make sure to NOT pour the paint into the soil as this can be absorbed by the soil and leave toxins that will last for years.