1. Balloon Decorators: Balloon Decorators is a company in Delhi that specializes in balloon decorations for all occasions, including birthdays. They offer a variety of balloon options, including foil balloons, balloon bouquets, and balloon arches. You can visit their website or call them to book their services.

2. Balloons Unlimited: Balloons Unlimited is another company in Delhi that offers balloon decoration services for birthdays. They can create customized balloon bouquets, balloon arches, and balloon walls, among other things. You can check out their website or contact them for more information.

3. Party Sharty: Party Sharty is an event planning and Birthday Balloon Decoration in Hyderabad that offers a range of services, including birthday balloon decorations. They have a team of professional decorators who can create customized balloon arrangements to suit your needs. You can visit their website or call them to book their services.

4. Balloon Wala: Balloon Wala is an individual balloon decorator in Delhi who offers balloon decoration services for birthdays. They specialize in balloon arches and balloon backdrops, but can also create customized balloon bouquets and other arrangements. You can contact them through their Facebook page or WhatsApp to book their services.

These are just a few options for birthday balloon decoration services in Delhi. You can do a quick Google search or ask for recommendations from friends or family members to find more options.