Step 1: Read the question.
The Supreme Court relaxed the old rule of locus standi so that public-spirited people could approach the Court for the rights of others. We must name this development.
Step 2: Understand locus standi.
Locus standi means the right to stand before the court. Earlier, only the person whose own right was hurt could file a case.
Step 3: See the problem with the old rule.
Many poor and illiterate people could not reach the court themselves. So their rights stayed unprotected.
Step 4: See how the Court solved it.
In the late 1970s and 1980s the Supreme Court allowed social workers, lawyers, journalists and NGOs to file cases for affected groups. This new method is called Public Interest Litigation, or PIL.
Step 5: Match with the options.
Relaxing locus standi is the very base of PIL. So Option 1 is correct. Judicial review of administrative action, individual petitions and Article 226 writ expansion are related ideas but they are not what this relaxation is mainly called.
Step 6: Final answer.
This development is the growth of Public Interest Litigation.
\[ \boxed{\text{The evolution of Public Interest Litigation.}} \]