Nearly 50% of India's mining industry, by output value, is concentrated in eight states: Odisha, Rajasthan, Chhattisgarh, Andhra Pradesh, Telangana, Jharkhand, Madhya Pradesh and Karnataka. Another 25% of the output by value comes from offshore oil and gas resources.[270] India operated about 3,000 mines in 2010, half of which were coal, limestone and iron ore.[271] On output-value basis, India was one of the five largest producers of mica, chromite, coal, lignite, iron ore, bauxite, barite, zinc and manganese; while being one of the ten largest global producers of many other minerals.[268][270] India was the fourth-largest producer of steel in 2013,[272] and the seventh-largest producer of aluminium.[273]
The theoretical generalization to more than one period is a multi-period wealth and income constraint. For example, the same person can gain more productive skills or acquire more productive income-earning assets to earn a higher income. In the multi-period case, something might also happen to the economy beyond the control of the individual to reduce (or increase) the flow of income. Changing measured income and its relation to consumption over time might be modeled accordingly, such as in the permanent income hypothesis.
Purchasing a rental property is another common way that individual generate an income stream.  It is very similar to investing, in that you take a sum of money to purchase the property, and the property returns a cash flow – rent.  You do have expenses related to this that are different from investing, such as a mortgage, utilities, property taxes, etc, which all must be taken into consideration when calculating a return on rental property.
As interest rates have been going down over the past 30 years, bond prices have continued to go up. With the 10-year yield (risk free rate) at roughly 2.55%, and the Fed Funds rate at 1.5% (two more 0.25% hikes are expected in 2018), it’s hard to see interest rates declining much further. That said, long term interest rates can stay low for a long time. Just look at Japanese interest rates, which are negative (inflation is higher than nominal interest rate).
In order to generate $10,000 in Net Operating Profit After Tax (NOPAT) through a rental property, you must own a $50,000 property with an unheard of 20% net rental yield, a $100,000 property with a rare 10% net rental yield, or a more realistic $200,000 property with a 5% net rental yield. When I say net rental yield, I’m talking about rental income minus all expenses, including a mortgage, operating expenses, insurance, and property taxes.
Most of us think of investment income as just the cash flow we get from bank interest, bonds, share dividends and property rents, some of which comes via a super pension.  But a more complete view is to also consider how growing the value of your investments can add to your spending potential.  This total return approach generates income from both income and growth to optimise spending from your portfolio across all market cycles, aligning cheap and expensive investments to your goals.