Under scrutiny for carbon trail of an Internet search, Google's senior vice president of operations, Urs Hölzle hit back at critics saying that the news about use of energy usage and pollution created by a search query is a gross overstatement.

The fire back from Google Inc. came after a story published in The Sunday Times said a Harvard University physicist had estimated that up to 7 grams of carbon dioxide is generated by a typical search on Google.

While the physicist, Alex Wissner-Gross, has been emphasizing "a definite environmental impact" of a search on Google, the company argument is that 7 grams, a blown up estimate, is slight in comparison to the carbon emitted by other activities, like driving.

Moreover, correcting the figures, Hölzle said that one Google search query releases a corresponding 0.2 grams of carbon dioxide. In a layman's language it implies that the greenhouse gas pollution by nearly 1,000 searches on Google equates to the amount put out by a car driving six-tenths of a mile, or one kilometer.

So far as the energy spent on one search query is concerned, Google estimates it to be 0.0003 kWh, or 1 kilojoule. In other words, it is less than the amount of energy burnt by an average person in ten seconds.

Hölzle also wrote on the blog: "We've made great strides to reduce the energy used by our data centers, but we still want clean and affordable sources of electricity for the power that we do use."