Why Punjab’s claim over Chandigarh is stronger than that of Haryana

Context:

Haryana Government recently suggested that it would be better if both Haryana and Punjab agreed on Chandigarh as a Union Territory and make their independent capitals and Benches of High Courts.

Why was Chandigarh created:-

Chandigarh was planned to replace Lahore, the capital of erstwhile Punjab, which became part of Pakistan during the Partition.
From 1952 to 1966 (till Haryana was carved out of Punjab), Chandigarh remained the capital of Punjab.
At the time of reorganisation of Punjab in 1966, the city assumed the unique distinction of being the capital of both Punjab and Haryana, even as it was declared a union territory and was placed under the direct control of the Centre.

What was announced then:-

The-then Prime Minister Indira Gandhi had announced that Haryana, in due course, would have its own capital and Chandigarh would go to Punjab.

Again, in 1985, under the Rajiv-Longowal accord, Chandigarh was to be handed over to Punjab on January 26, 1986, but the Rajiv Gandhi government withdrew at the last minute.

Recent Developments:

In 2018, Haryana CM Manohar Lal Khattar suggested to set up a special body for development of Chandigarh, but the Punjab CM rejected it, saying the city “indisputably belonged to Punjab”.

Haryana, on its part, has been demanding a separate High Court and even locked horns with Punjab by passing a resolution in the Vidhan Sabha demanding 20 rooms in the Vidhan Sabha complex that have been in the possession of Punjab.