There were many causes of the War of Independence of 1857. They can be divided into political, religious, military, economic and social causes. The East India Company was aiming to annex all the states of India like Avadh, Tanjore, Jhansi, Satara, etc. That’s why they introduced systems like Doctrine of Lapse by which Indian states could be taken over by the Company in case there was no male heir to the throne of the state. This provoked the rulers like Nana Sahib, the adopted son of Peshwa and Lakshmi Bai, the Rani of Jhansi. The Company also declared that after the death of the then Mughal emperor, Bahadur Shah Zafar, his family had to move out of the Red Fort and his successors were also forbidden to use the title of emperor. All these attempts alienated both Hindu and Muslim Indians who realized that the White men were intending to devour their lands.
The people of India at that time were highly concerned about their religion and religious rites. For them the most sacred thing was their faith. But when they realized that the Company was promoting Christianity in their land they became furious. In fact the Christian missionaries all over India were being patronized by the British government and in 1855 the priests like E. Edmund professed that the whole of India should be under one religion, i.e., Christianity. Similarly the introduction of some social laws added fuel to fire. For instance, the English government banned Satti (Hindu practice of burning the widow along with the dead body of her husband), and allowed the widows to remarry. Such legislations badly hurt the feelings of Hindus. In the military setup they introduced some regulations that injured religious sentiments of the Indians. For example, under the military rules the Indian soldiers were forbidden to have beards or wear turbans or put tilaks on their foreheads. These regulations made Indians realize that their faiths were in jeopardy.
Whenever the English annexed any state of India into their domain they dismantled its army and disemployed the local soldiers. Thus after having been enslaved the second shock the local soldiers had to bear was unemployment that made them despise the foreign invader. Besides, the English invariably maintained discrimination between their soldiers and the Indian soldiers in respect of salaries and fringe benefits with the result that the disheartened soldiers made up their minds to fight against the English.
There were economic causes as well. During the rule of the Mughals, not only the Muslims but also the Hindus would be appointed on all important positions but by the English the Muslims and the Hindus both were deemed as untrustworthy and consequently all the higher posts were held by the White men. The natives were either turned jobless or appointed on lower levels of the state departments. The East India Company that was eager to amass wealth out of the trade considered India no more than a field of producing raw materials for the industries of England. The subsidiary system with additional taxes even on uncultivated lands added fuel to the fire and economically devastated the common Indians.
In addition to these reasons there was an immediate cause that coerced the Indians to go for war. In the words of Lord Canning, Lawrence and Syed Ahmed Khan it was, indeed, the most significant cause. For a new Enfield rifle introduced in the early period of 1857 the cartridges were covered with some animal fat that was supposed to be either of cow or a boar. Before using these cartridges they were to be cut by teeth. Since the cows were sacred for the Hindus and pigs were haram for the Muslims both of them refused to carry such rifles. But their English officers used force that offended the Hindus and Muslims alike and thus all these causes instigated the war in India to which we call the War of Independence 1857.