Can someone explain to me what is clubbed income and when does it apply??
The situation in which the income of another person is included in the income of the taxpayer is called clubbing of income. In certain special cases, the income of other person is included (i.e. clubbed) in the taxable income of the taxpayer. Here, he will be liable to pay tax in respect of his income (if any) as well as the income of other people too.
To understand in detail about what clubbed income us and when does is apply, please refer to the article.