I could not run a database consistency check on this database. I had to do the following things to recover the database:
1. Put the database in single user mode with immediate rollback option.
2. Set the database in emergency mode
3. Ran the database consistency check with repair_rebuild option but it didn't work.
4. Ran the database consistency check with REPAIR_ALLOW_DATA_LOSS option. The consistency check ran without any consistency errors.
5. Database cameup online in the single user mode. I switched it to multi user mode.
Now, the database is accessible.