Hi, I am doing SEO for a website that deals in 4-wheeler tyres. While reviewing the organic traffic in Google Analytics, i noticed some keywords that are completely irrelevant to the theme of the website. Some are porn related terms while some are like google, yahoo, laptops, youtube etc. It seems someone is doing negative SEO for my website, as a result of which a decent number of searches are coming from these irrelevant terms. What should i do to block traffic from such terms as this may harm my website's performance in search engines. Please suggest a solution as soon as possible.