Well, it is historical, but it also has to do with the fact that India is a developing country and Canada is a developed country. Generally speaking, developed country tariffs have decreased considerably more than those of developing countries in multilateral trade negotiations, as well as bilateral and regional agreements.
Now, you have to understand the difference between the bound tariff and the applied tariff. The bound tariff for India, for Brazil, and for others—but not China—can be considerably higher than their actually applied tariff under WTO and other rules. But generally speaking, the difference is the history of developed versus developing country economies.