Tax on income from different sources

Just adding to this question, is it legal to work on a consultant fee for 2 different companies

Income Tax Act, 1961 provides calculation of tax on gross income from all sources, which include income from salary, house, capital gains, business & profession and other sources. Subsequently net taxable income is calculated and tax on income, as applicable, is paid.  

Seek professional service of a local chartered accountant.

yes as per the statement three way of income he is getting . Once from salary, another from income from profession or other sources, income from house property . you need to show in the appropriate heads of income 

Income from all sources has to be declared/shown in the IT return under respective heads and Gross income to be arrived at. Based on the Gross income minus Standard Deduction if eligible and other exemptions, tax shall be computed which needs to be paid. It is better to engage a Chartered Accountant/Income Tax Practitioner to prepare the Return at least for the first time.

Is his employer deducting TDS from his salary?

Income which is not exempt and cannot be charged under the heads of salary, income from house property, profits and gains from business or profession, or capital gains, form income from other sources for taxation purpose.

All dividends received are taxable under the head of income from other sources.

Interest from deposits and bonds are also taxed under Income from other sources.

One-time income by way of winnings from lotteries, crossword puzzles, races including horse races, card games, gambling or betting of any form is treated as income from other sources.
Gifts such as any sum of money and movable or immovable property that’s received without consideration are also taxable under this head.

The income which is not exempt and can not be shown under other heads, should be shown under income from other sources while filing income tax return (ITR).

Incomes that fall under "income from other sources"