There's no denying that Ash Ketchum is a great Pokémon trainer--he consistently has shown that he cares about the well-being of his Pokémon and routinely lets them make their own decisions about battling and traveling with him.
And although nowadays Ash is about to hit the top 8 of the World Coronation Series, as he moved through the Indigo League of the Kanto region and the Johto League of the Johto region, fans couldn't help but notice that a shocking amount of Ash's accumulated badges weren't technically won by defeating gym leaders. It calls into question whether or not he should have been given these badges at all.
Kanto: Boulder Badge
Even starting out his journey in one of the best-ranked Pokémon hometowns, Ash was awarded a badge for something other than his battle expertise. In Pewter City, Ash faced Brock's Onix with Pikachu, an admittedly mismatched fight, and forfeits the first time after Pikachu is in distress.
During a rematch, Ash stops the battle after the gym's sprinkler system gives Pikachu an unfair advantage over Onix. Brock chases after Ash and offers him the Boulder Badge because of his compassion towards Pokémon--even though Ash would have likely lost both gym battles within normal conditions. He just didn't have the right kind of Pokémon for a Rock-Type gym.
Kanto: Cascade Badge
Consequently, Ash doesn't truly win badges from either of his main travel companions. Ash was simply offered the badge by the Sensational Sisters without a battle before Misty intervened and challenged Ash.
Misty is one of the best gym leaders, according to Ranker, and her battle against Ash was very close. However, their match is interrupted by Team Rocket trying to steal the Water-Type Pokémon and Ash gets the Cascade Badge for stopping them. Although he could have won the gym battle, fans will never know if would have earned the badge the right way.
Kanto: Marsh Badge
After earning the Thunder Badge using Pikachu's agility against Surge's Raichu, Ash traveled to Saffron City, where Sabrina and her Psychic Pokémon are in charge of the gym. After losing his first attempt, Ash goes back to the gym with a Haunter.
When the Haunter disappears mid-battle, Sabrina kidnaps Brock and Misty, turning them into dolls, and Ash narrowly escapes with her father. Ash returns, sans Haunter, to battle Sabrina again, and Haunter appears. He makes Sabrina laugh by making faces and breaks the spell she's under. Again, Ash is given a badge because of integrity and helping others instead of pure merit.
Kanto: Rainbow Badge
Ash wasn't even given a chance to battle at the Celadon gym at first. After hearing that he thinks perfume is a waste of money, the gym leaders stamp a large red "X" on Ash's face and tell him he's not welcome.
But, after Team Rocket tries to steal the gym's perfume formula during Ash's eventual battle, one of their bombs causes a huge fire inside the gym. Ash goes back in to save the gym leader's Gloom, and she gives him the Rainbow Badge for his bravery. While it was a brave act, it didn't prove anything about Ash's skills or Pokémon.
Kanto: Volcano Badge
The Volcano Badge that Ash wins on Cinnabar Island is a point of contention for some fans. While he did battle the gym leader and win, fans have debated on sites like Quora about whether Ash won the battle, or Charizard did.
Charizard is one of Ash's strongest Pokémon, but he was also one of his most disobedient at the time. When Charizard faced off against Magmar, he didn't listen to any of Ash's commands or strategies and won the battle with his own decisions. So, technically, Ash's abilities as a trainer did not win the battle or earn the badge.
Kanto: Earth Badge
When the group gets to Viridian City, it's revealed that Giovanni, the leader of Team Rocket, is the gym leader there. He very easily defeats Gary--who, at this point, has won more badges by merit than Ash has.
However, Giovanni is called away and leaves Jessie and James to face Ash for his match. Team Rocket may have some strong Pokémon, but Ash has faced them and won many times. Even with the addition of Giovanni's Pokémon, Jessie and James weren't real gym leaders and had terrible strategy. Ash gets the Earth Badge when it falls out of Jessie's pocket as they're blasted away.
Johto: Plain Badge
When Ash gets to the Johto region, the ratio of badges he earns in battle vs not is very different from the Kanto region. But, it does still happen in some of the episodes. It first happens when he is battling for the Plain Badge against Whitney and Miltank.
In true Ash fashion, he outrightly loses his first battle attempt and later challenges Whitney to a rematch after they work together to defeat Team Rocket, who were trying to steal food. During the rematch, Ash only defeats one of Whitney's Pokémon, Miltank, before she decides to give him the Plain Badge--even though the battle was supposed to be three vs three.
Johto: Glacier Badge
Although Ash had a very long streak of valid wins in the Johto League, one of his closing matches of the region wasn't technically won in battle. After being lost in Ice, gym leader Pryce is reunited with his Piloswine the day before his gym battle with Ash.
When Ash was preparing to battle the Ice-Type Pokémon, he thought he would have a major advantage. To his surprise, Pryce's Pokémon go head to head with Ash's and it's looking like Ash may lose. Because he doesn't want to exhaust or hurt Piloswine, Pryce stops the match and forfeits, which brings Ash back to getting badges without actually winning the gym battles.