Explanation
Why Correct: Public Interest Litigation (PIL) allows any citizen to approach a court for enforcement of public rights, and it is a direct expression of judicial activism. The Supreme Court expanded the scope of Article 32 and Article 226 through PIL, enabling courts to take suo motu cognizance of issues affecting the public at large.
Distractor Analysis: Judicial Review is the power of courts to examine the constitutionality of legislative and executive actions, a separate function under Articles 13, 32, 131-136, 143, 226, 227, 246, 251, 254, 372, and 395. Federalism is a system of government where power is divided between a central authority and constituent units, a structural principle, not a judicial concept. NITI Aayog is a policy think tank established in 2015 to replace the Planning Commission, with no direct connection to PIL.
Takeaway: The first PIL in India was filed in 1979 by Justice P. N. Bhagwati in Hussainara Khatoon v. State of Bihar, addressing undertrial prisoners' plight, and the concept was formalized in S. P. Gupta v. Union of India in 1981.