https://www.scconline.com/blog/post/2023/02/24/ad-hoc-service-judicial-service-seniority-elevation-high-court-judge-article-217-supreme-court-andhra-pradesh-high-court-legal-updates-knowledge-research-law-news/
Ad-hoc judicial service does not count as ‘judicial service’ for elevation as a High Court judge: Supreme Court