Why did the empowered committee accept the studies done by Annamalai University in Tamil Nadu in preference to the finding of the professors of Indian Institute of Technology (Roorkee and Delhi)? Was it bias? Or did not it have something to do with the quality of the studies.

It is well known that some of the studies were done quickly, just months before they were to be presented before they were to be submitted to the court. The draft of the first part had come with several mistakes that  officials of the Mullaperiyar Special Cell (Kerala) had to go to Delhi to get them corrected. The second part of the seismic stability studies could not even be completed and submitted to the Supreme Court in time.

Expert-Eyes had earlier discussed the errors in the article  Mullaperiyar and environmental impact of raising the water level. Readers and experts can look at the structural stability analysis at http://expert-eyes.org/mullaperiyar/tremours/index.html

Why did the reputed experts of IIT wanted the study to be restricted to official use only. Were they avoiding public scrutiny? If one looks at the executive summary, it has more background than findings. Though Water Resources Minister P. J. Joseph had told a press conference in reply to questions that the Irrigation Design and Research Board would publish the PMF and flood routing studies on Mullaperiyar Dam done by IIT, Delhi, and Seismic Stability of Mullaperiyar Composite Dam done by IIT, Roorkee, on its Web site; it is yet to do so. The Department is also refusing to release copies of these and other studies under the Right to Information Act.

See:
Mullaperiyar: Directive against disclosure of dam break analysis
Mullaperiyar: behind the veil
IIT Roorkee seismic report has (only) value of paper says TN