When planning return gifts for a birthday party in Mumbai, you have a plethora of options that can reflect the city's vibrant culture. Consider including local snacks like vada pav or Bombay mix, which are iconic street food items. Another great idea is to provide guests with small packets of traditional spices commonly used in Mumbai's diverse cuisine, such as pav bhaji masala or garam masala blends. These edible treats can offer a taste of Mumbai's culinary delights.

For a more personalized touch, you can create customized Mumbai-themed merchandise, such as t-shirts, keychains, or mugs featuring iconic landmarks like the Gateway of India or Marine Drive. These items not only serve as mementos of the birthday celebration but also help guests connect with the unique spirit of Mumbai.