For context, the following is from Wikipedia

Although numbers are unreliable, it is generally accepted that the most widely watched events worldwide are international sporting events such as the Summer Olympic Games, FIFA World Cup, and the Cricket World Cup with annual events such as the CMG New Year’s Gala in China, Super Bowl in the U.S., the Indian Premier League in India and the UEFA Champions League finals in Europe picking up large regional audiences.

Other broadcasts frequently claimed to have broken records include news events such as the 1969 Apollo 11 Moon landing, funerals of significant figures such as Michael Jackson, Diana, Princess of Wales, or Elizabeth II, and music events such as the 1985 Live Aid benefit concert, 1993 Super Bowl Halftime Show, or the CMG New Year’s Gala that is recognised by Guinness World Records as the world’s most watched television programme.

List of most-watched television broadcasts - Wikipedia

Most watched TV broadcasts in India

ShowEpisodeMillionsDate
2025 Indian Premier League RCB vs PBKS (final) 578 3 Jun 2025
2011 Cricket World Cup final Sri Lanka vs India (final) 340 2 Apr 2011
2015 Cricket World Cup Australia vs India (semi-final) 309 26 Mar 2015
2023 Cricket World Cup India vs Australia (final) 300 19 Nov 2023
2019 Cricket World Cup India vs New Zealand (semi-final) 283 16 Jun 2019
2015 Cricket World Cup India vs Pakistan (group stage match) 282 15 Feb 2015
2015 Cricket World Cup India vs West Indies (group stage match) 262 16 Jun 2019
2015 Cricket World Cup India vs South Africa (group stage match) 257 22 Feb 2015
2015 Cricket World Cup India vs Bangladesh (quarter-final) 251 19 Mar 2015
2025 ICC Champions Trophy India vs New Zealand (final) 230 9 Mar 2025
2025 ICC Champions Trophy India vs Pakistan (group stage match) 206 23 Feb 2025

Most watched TV broadcasts in the USA

BroadcastMillionsDate
Apollo 11 Moon landing 125–150 20 Jul 1969
Super Bowl LIX 133.5 9 Feb 2025
Super Bowl XXVII Halftime Show 133.4 31 Jan 1993
Super Bowl LVIII 123.7 11 Feb 2024
Super Bowl LVII 115.1 12 Feb 2023
Super Bowl XLIX 114.4 1 Feb 2015
Super Bowl LVI 112.3 13 Feb 2022
Super Bowl XLVIII 112.2 2 Feb 2014
Super Bowl 50 111.9 7 Feb 2016
Super Bowl XLVI 111.3 5 Feb 2012
Super Bowl LI 111.3 5 Feb 2017

China Central Television’s main evening news broadcast Xinwen Lianbo has a daily audience of around 135 million people. Chinese boxer Zou Shiming’s professional boxing debut on 6 April 2013 generated an estimated 300 million viewers. Another professional boxer Qiu Xiaojun attracted around 200 million people for his fight against Ghanaian fighter Raymond Commey on 12 February 2016.

And

Euro 2024 tops the ranking of the world's most streamed sports events in 2024, beating the Paris Olympics

Euro 2024 topped the ranking of the world’s most streamed sports events in 2024, beating the Paris Olympics — Inside World Football