Explanation:

- Option 1: Indore

- Indore has consistently been recognized for its cleanliness.

- It bagged the first rank as the cleanest city of India under SwachhSurvekshan League 2020.

- Indore's efforts to maintain and improve its sanitation infrastructure are noteworthy.

- This is the correct answer.

- Option 2: Jhansi

- Jhansi is making strides in cleanliness but hasn't ranked first.

- It is part of the ongoing national cleanliness drive, but Indore leads in rankings.

- Option 3: Bhopal

- Bhopal is one of the cleaner cities but hasn't topped the list like Indore.

- It continues to improve under national cleanliness initiatives.

- Option 4: Gwalior

- Gwalior is part of the Swachh Bharat mission.

- However, it is not the top-ranked city in cleanliness as compared to Indore.