Shiv Sena (UBT) leader Aaditya Thackeray on Friday criticised Maharashtra CM Eknath Shinde's directive to BMC to install air purifier towers in Mumbai and called it an "eyewash". "As a former environment minister...I can vouch that these towers are an absolute...waste of public money, at large," he tweeted. Government must focus on identifying sources of pollution, he added.