"The incident took place this evening at the newly-built Indian Institute of Information Technology (IIIT) when final touches were being given to the dome and the stage," Inspector General of Police, Raipur Range, GP Singh told PTI.
The IIIT building in Naya Raipur will be inaugurated by Modi on Saturday, where he will also address a public gathering.
"While the work of the dome was underway, suddenly weather changed and a severe storm hit the place damaging a portion of the dome which fell on the police personnel and workers, who were present there," the IG said.
The injured were rushed to different hospitals of the capital, including Ramkrishna Care, NHMMI and Dr Bhimrao Ambedkar Hospital, Singh added.
Chhattisgarh Chief Minister Raman Singh immediately convened a meeting of senior officials to take stock of the situation in this regard, he said.