Being in the great sub continent of India, you might have access to bamboo wood. If bamboo wood was more available in the states, I would use it for all of my mold boxes.
Just about any dry wood will work but the most important thing is the thickness of the wood you use. It should be at least an 1/8 inch (3cm)thick ,this will prevent the wood from warping if it gets wet. Also if a board is repeatedly heated with moisture, like during gel phase, it can warp. You don't need to go any thicker than an 1/4 inch (6cm), it will make it unnecessarily heavy. I also recommend that you nail or screw it together along with using wood glue. Glue by itself is more prone to heavy warping.
Last thing, if you have any native wood that grows in wet areas, like cypress in the United States, that wood is better suited for what you are doing.