Indian incense can be divided into two categories: masala and charcoal. Masala incenses are made of dry ingredients, while charcoal incenses contain liquid scents. Masala incenses have several subgroups.
Masālā is a word in Hindi (and other Indian languages) meaning "spice mixture". It is commonly used when referring to curries or other food dishes. Masala incenses are made by blending several solid scented ingredients into a paste and then rolling that paste onto a bamboo core stick. These incenses usually contain little or no liquid scents (which can evaporate or diminish over time).
Durbars are a sub-group of masala incense. They often contain ingredients entirely unfamiliar in the West and contain very complex scents. They are usually very slow-burning and are quite sweet and spicy in scent. They contain both solid and liquid perfumes in a binder which never quite dries out, making the incense sticks soft to the touch.
Champas are a sub-group of durbars. They contain a natural ingredient indigenous to India called "halmaddi". Halmaddi is a grey semi-liquid resin taken from the Ailanthus Malabarica tree. It smells like the flowers of the plumeria tree. Plumeria flowers are known as champa flowers in India, hence the name of the incense group. Halmaddi is hygroscopic which means it absorbs moisture from the air. This can cause champa incenses to have a wet feeling to them. Nag Champa is probably the most famous incense of the champa group.
Dhoops are another masala sub-group. They are an extruded incense, lacking a core bamboo stick. Many dhoops have very concentrated scents and put out a lot of smoke when burned. The most well-known dhoop is probably Chandan Dhoop. It contains a high percentage of Sandalwood.
Charcoal incenses are made by dipping an unscented "blank" (non-perfume stick) into a mixture of perfumes and/or essential oils. These blanks usually contain a binding resin (sometimes sandalwood) that holds the sticks' ingredients together.