If you're talking about E-numbers:
E500 Sodium carbonates
E503 Ammonium carbonates
Baking soda is usually sodium hydrogen carbonate. It is made from sodium chloride (derived from seawater or rocks), ammonia and calcium carbonate. Ammonia is made by reacting nitrogen from the air with hydrogen, which may be produced from water or from hydrocarbons. ...
The E stands for Europe so this advice is valid for all the EU.
Here or here you can find a list of those E numbers that are not vegetarian/vegan and here you can find another which also specifies the different functions of the veg-friendly ones.
You need to ask the producer to determine whether any animal-based food additives were used.
The rules for the green dot vegetarian mark are defined by the Food Safety and Standards Authority of India (FSSAI). All food is considered vegetarian unless it contradicts this definition:
“Non-Vegetarian Food” means an article of food which contains whole or ...