This chapter is the entry point to the Internal Security section of GS Paper III. It builds the map that every later chapter fills in: what counts as an internal security threat, where in India each type is concentrated, and why development, governance and security cannot be treated separately.

What UPSC asks

Mains GS III (most of the weight): the development–extremism link, the Left Wing Extremism (LWE) strategy, the role of tribal rights laws (PESA, Forest Rights Act), and a balanced assessment of security-centric versus development-centric approaches.
Prelims (occasional): the Naxalbari uprising, the ban on CPI (Maoist) under UAPA, PESA 1996, the Forest Rights Act 2006, and the SAMADHAN doctrine.

Key sub-topics

Sub-topic	What to know
The four theatres	Jammu and Kashmir, the North-East, LWE areas, terrorism in the hinterland
Left Wing Extremism	Origin (Naxalbari, 1967), CPI (Maoist) (2004), the “Red Corridor”
Development deficit	Land alienation, displacement, forest rights, weak local governance
Government response	National Policy and Action Plan (2015), SAMADHAN (2017), development schemes
Rights and legitimacy	PESA 1996, Forest Rights Act 2006, Fifth Schedule, Nandini Sundar (2011)

Start with the topic page, then test yourself with the revision sheet and practice set.