I have registered for CCA 175 exam and I want to practice using cloudera Quick start VM 6.1.1 but it is not available anywhere to download.
Is there any alternate VM available to continue my practice which is very similar to cloudera VM 6.1.1?
There was never a Cloudera QuickStart VM based on CDH 6.1.1 released to the public. The most recent Cloudera QuickStart VM was based on an installation of CDH 5.13, and is outdated and nearing end of support, so it is no longer available for download despite what you might think when you see various hyperlinks on the Cloudera website labeled "QuickStart VMs".
Just going on the information available on this page, (scroll down to Exam delivery and cluster information), it looks like CCA175 is based on CDH 6.1.1, which is much closer to up-to-date. You can download CDH 6.1.1 by using this page, but it will not deliver a prepackaged standalone, single-node VM-based environment.