Writing and publishing an eBook has become a widely popular means of earning passive income in recent years. eBooks on non-fiction topics like online marketing, business development, career advice, and the like are especially successful. While fiction eBooks are also good sellers, the market for them is much more competitive as compared to non-fiction ones. Once you've written an eBook, you can put it up for sale on platforms like Amazon's Kindle Direct Publishing or Apple's iTunes Connect.
Engineering is the largest sub-sector of India's industrial sector, by GDP, and the third-largest by exports.[177] It includes transport equipment, machine tools, capital goods, transformers, switchgears, furnaces, and cast and forged parts for turbines, automobiles and railways. The industry employs about four million workers. On a value-added basis, India's engineering subsector exported $67 billion worth of engineering goods in the 2013–14 fiscal year, and served part of the domestic demand for engineering goods.[178]
We encourage a more holistic, total return approach to your sustainable spending needs from investments.  An improved portfolio includes a wide range of income sources providing both cash flow and capital growth.  Your chosen blend should match your overall financial goals, considering your tolerance for risk, time frames, income and liquidity needs with a spending rate that sustains the investor’s wealth.
"But for our jobs, for how we make money, I think many of us — most of us — have one way we make money. It can be very risky. I've really come to believe, and have done a lot of research over the years, that one of the best ways that we can create real, legitimate professional stability for ourselves is by choosing to cultivate multiple income streams.
Portfolio income can come from multiple sources – interest/bond coupons, stock dividends, financial strategies including derivatives and capital growth.  Each offers some cash flow and some also offer potential capital gain with some risk from liquidity and volatile prices.  In this low-yield environment, many investors rely too heavily on cash flows and to pursue this are venturing further into riskier areas than they’d normally consider.