Here is the answer to the question for UPSC Mains aspirants, with the key points and headings bolded:

Role of the First World War in Providing New Opportunities for the Militant Nationalist Movement:

1. Weakening of the British Empire: The First World War significantly weakened the British Empire, both financially and militarily. This provided an opportunity for the militant nationalist movement to capitalize on Britain’s vulnerability and intensify their struggle for independence.
   Recent example: The ongoing protests against the Citizenship Amendment Act (CAA) and the National Register of Citizens (NRC) in India, which have been fueled by the government’s perceived weakening of democratic institutions and the rule of law.
2. Increased Mobilization of the Indian Masses: The First World War led to an increased mobilization of the Indian masses, as the British government sought to recruit more soldiers and raise resources for the war effort. This provided the militant nationalist movement with a larger pool of potential supporters and recruits.
   Recent example: The farmers’ protests in India, which have seen the participation of a large number of farmers and rural communities, reflecting the increased mobilization of the Indian masses.
3. Radicalization of the Nationalist Sentiment: The First World War also led to the radicalization of the nationalist sentiment, as the promises of self-governance and greater autonomy made by the British government during the war were not fulfilled in the aftermath. This fueled the growth of the militant nationalist movement.
   Recent example: The rise of Hindu nationalist movements in India, which have adopted a more radical and confrontational approach to the nationalist struggle, as seen in the ongoing debates over the CAA and the NRC.

Challenges Faced by the Militant Nationalist Movement:

1. Increased Repression by the British Authorities: The First World War also led to increased repression by the British authorities, who sought to quell any form of dissent or challenge to their rule. This presented a significant challenge to the militant nationalist movement.
   Recent example: The government’s use of the Unlawful Activities (Prevention) Act (UAPA) and other laws to crackdown on civil society organizations and activists, which has been criticized by human rights organizations as a violation of democratic principles.
2. Divisions within the Nationalist Movement: The First World War also led to the emergence of divisions within the nationalist movement, as some factions were willing to collaborate with the British government in exchange for concessions, while others remained committed to the goal of complete independence.
   Recent example: The ongoing tensions between the different factions of the Indian National Congress, as well as the emergence of regional and ideological political parties, which have posed challenges to the unity of the nationalist movement.
3. International Geopolitical Factors: The First World War also introduced new international geopolitical factors that influenced the dynamics of the nationalist movement, as the British government sought to leverage its alliances and relationships with other powers to maintain its control over India.
   Recent example: The ongoing geopolitical tensions between India and China, which have had implications for the country’s domestic political landscape and the nationalist movement.

Overall, the First World War provided both new opportunities and challenges for the militant nationalist movement in India, leading to a complex and evolving landscape that continues to shape the country’s political and social dynamics