This report is from this week's CNBC's "Inside India" newsletter which brings you timely, insightful news and market commentary on the emerging powerhouse and the big businesses behind its meteoric rise. Like what you see? You can subscribe here.

The big story

The putrid burning smell, difficulty breathing and chest congestion - that is what Delhi resident Sheetal Sharma has been experiencing since end-October, no thanks to the toxic air enshrouding India's National Capital Region (NCR).

"Delhi feels right out of a dystopian movie. The air quality deteriorated very quickly post-Diwali from poor to severe in a matter of hours and has continued that way till now," Sharma told CNBC's Inside India, alluding to the popular national festival.

The air quality index (AQI) - which measures the level of pollution in the air - has risen significantly in the last few months. The metric peaked in November and subsequently edged down, only to nudge up to around 478 in the National Capital Territory of Delhi, which alongside several districts from surrounding states makes up the NCR, on Thursday. The reading remains in the hazardous range per classifications from India's Central Pollution Control Board.

The government body considers a good AQI reading to be between zero and 50. Readings between 200 and 400 are classified as "poor" or "very poor" while anything above 500 is deemed "severe" for it has a serious impact on people with existing ailments.

The high AQI readings have pushed the government to direct schools to move to hybrid mode for some grades and stagger the working hours of civil servants. It has also imposed restrictions on vehicle usage in Delhi and adjoining regions with the view to curb emissions.

Still, Delhi's prolonged high AQI reading has already taken a toll on many of its denizens. Sharma recounts that she had "no respite," despite several courses of medication and undergoing treatment to clear her nasal passageways.

Relief only came when she "escaped" to a village near Nainital, some 300 kilometers away from Delhi. The AQI reading was just 65 there, allowing her "cough and cold to disappear within hours, without medical aid," Sharma, who works at a tech company, said.

Unlike Sharma, many in Delhi - particularly those in labor-intensive roles - have not been able to escape the pollution.

Thirty-seven-year-old Dinesh Kumar is one such person. The auto-rickshaw driver hails from Patna in the province of Bihar, over 1,000 kilometers east of Delhi. He was forced to find higher-paying work in the capital city to support his aging parents and school-going children.

Kumar dreads the winter months when pollution levels are heightened and people stay indoors. However, he says he does not have the means to move out of Delhi to seek employment in this period.

"My auto is empty on most days [during this time]. At most, I get one or two passengers now, compared to around 20 at other times of the year," he laments, using the local term for a motorized, three-wheeled vehicle.

When he does drive, he says he is "constantly coughing." "I feel like there's chili in my eyes because I'm [tearing] and cannot see. If I stop working, my family will have no money" he told CNBC's Inside India.

Delhi's smog conundrum is a yearly problem permeating through the Indo-Gangetic plains - or northern states in India between October and December.

A geographical disadvantage

With Delhi's smog problem taking centerstage every winter, the natural assumption is that the lower temperatures, or activities like agricultural stubble burning which happen in this season have a large part to play in elevating pollution levels.

However, Anumita Roychowdhury executive director of research and advocacy at the Centre for Science and Environment, argues that the "explosion" in air quality metrics is not because of a sudden spike in pollution-related activities in this season.

"Pollution is high and remains elevated all throughout the year. It is not that there is pollution only during winter," she explained. Instead, she attributes the worsening readings to adverse meteorological conditions in the Indo-Gangetic plains where pollution that is already in the air from different sources gets trapped and has no wind to blow it away.

Delhi, and other northern Indian states are most susceptible given its "geographical disadvantages," Roychowdhury explained.

"Mumbai or Chennai have much better natural ventilation because they have the open sea. So, even though pollution levels are very high in Mumbai, it does not accumulate, and the concentration doesn't become as big as northern India, because the open sea, the natural ventilation index there is much better," she added.

For its part, the Delhi government has undertaken several measures to curb pollution. In the past, it has even experimented with restricting the number of vehicles on the road based on their license plate numbers. However, Roychowdhury stresses that other states in northern India will now need to step up their efforts in addressing this problem.

"Pollution does not follow boundaries," she said, quoting estimates from the Indian Institute of Tropical Meteorology, showing that 70% of particulate matter 2.5 is coming from the larger region outside Delhi.

Particulate matter 2.5 refer to particles in the air like smoke, soot, bacteria and pollen with a diameter that is 2.5 micrometers, or around the thickness of a single strand of hair.

A $95 billion cost

The longer-term implications of Delhi's poor air quality extend beyond just compromising residents' health and well-being to creating ripples in the economy.

Data from Dalberg Advisors, Clean Air Fund, Blue Sky Analytics and trade body CII, highlights that India's capital New Delhi (which is part of NCR) loses 6% of its annual Gross Domestic Product (GDP) to air pollution.

Meanwhile, air pollution costs Indian businesses $95 billion or around 3% of India's Gross Domestic Product (GDP) every year, the same report published in 2021 showed.

Those in the middle and lower-income groups are often the worst hit.

"The smog disproportionately affects the poor because the government is temporarily shutting down or phasing out polluting industries which absorb a significant number of semi-skilled and unskilled labor on daily wages," Sumedha Dasgupta, senior analyst at the Economist Intelligence Unit (EIU) said.

Elsewhere, she noted that consumer-facing sectors such as retailers have also felt the pinch as people are now veering towards online shopping. Similarly, businesses servicing India's booming wedding industry have been affected by consumers postponing their celebrations because of the poor weather.

The interconnected nature of India's cities means that the economic weakness in Delhi could eventually extend to other parts of India.

"There is a domino effect in many areas," Dasgupta said, using the construction industry as an example. Halting activities in Delhi would in turn mean stopping the purchase of sand from Bihar as well as cement and raw materials from another part of India, which would then impact the labor and efficiency levels in those states.

"So in the long-term you are slowing down the economies of those regions as well," Dasgupta explained.

What is needed?

While the seasonal smog is likely to taper off by the end of winter in January, it is imperative for Delhi - and the wider north India region - to craft strategies to minimize its yearly recurrence.

Failure to do so may bring about other problems such as pushing people and investments out of the highly-polluted areas and into other parts of India.

That will end up creating a "migration burden" and add pressure to the infrastructure in other major metros like Mumbai, Bangalore or Hyderabad, which may have "to take on the load of people who can't live in or are migrating out of Delhi," Dasgupta said.

"So, it can certainly create a lot of issues on a national level, in terms of loss of productivity and traction in industries," she added.

For starters, Roychowdhury suggests a shift away from "middle-class environmentalism" towards a more solution-based approach to address the problem. At a consumer level, this involves reducing the usage of cars and opting for public transport instead, where possible.

Meanwhile, she notes that businesses can look into sustainable and environmentally-friendly financing strategies. This would involve investing in infrastructure that minimizes the use of private transportation, as an example.

"We need to repurpose our investment that otherwise goes into car-centric infrastructure, and divert that funding towards building infrastructure for walking, cycling and public transport, that will certainly give us a much bigger pay off and help us to prevent and control pollution more efficiently," Roychowdhury added.

She argues that businesses can also look into repurposing the residue of the crops that farmers are burning. There have already been instances of this in Delhi and the NCR, where biomass-based fuels absorbing agricultural waste and crop residue are being used by the industrial sector in place of natural gas.

These improvements are part of a long road to addressing a major problem in India. If handled well, it can mean that businesses embrace Delhi, while residents like Sharma and Kumar remain healthy, bolstering both their income and the nation's economic growth.

Need to know

The lower-than-expected economic growth in India's fiscal second quarter is a "temporary blip." That's according to the country's finance minister Nirmala Sitharaman. "This lower growth situation is no different from the earlier years when Lok Sabha elections were conducted," Sitharaman said, referring to the June elections in India's lower house of parliament. She also noted that government capital expenditure has risen 6.7% year on year.

India's trade deficit in November was wider than expected. In the April to November period, India's imports rose 8.35% compared with its export growth of 2.17%, year on year. That's led to a trade deficit of $37.84 billion in November, higher than the $23 billion expected by a Bloomberg survey. In October, that figure came in at $27.1 billion.

Earnings growth in India has faced challenges recently. Disruptions caused by the monsoon and elections in India have hit earnings in the last few quarters, according to Rohit Shimpi, Fund Manager at SBI Mutual Fund. That said, he says the economy looks set to pick up as companies and the government accelerate their capital expenditure.

Global markets have lagged behind the U.S. this year. Year to date, the iShares MSCI ACWI ex U.S. ETF has risen 3.17%, compared with the S&P 500's 23.87% increase during the same period. Strategists see more bumps in 2025 for global markets. However, "India is still the market to beat" neat year, one strategist said. [For subscribers only]

What happened in the markets?

Indian stocks continued to fall this week. The Nifty 50 index is down 3.3% since last Friday's close. The index has risen 10.2% since the start of the year.

The benchmark 10-year Indian government bond yield has moved up by over 5 basis points since the end of last week, to 6.786%.

On CNBC TV this week, Carl Ashton, investment counselor at Citi Private Bank, said that the bank is maintaining an overweight stance on India. Even though stock prices are around 20- to 22-times earnings, corporate earnings are growing in the region of high double-digits. India's projected 7% growth in gross domestic product next year might help recover corporate earnings as well. Hence, the valuation of Indian equities looks "reasonable," Ashton said.

Meanwhile, Puneet Gupta of S&P Global Mobility, said that India and Tesla have a mutually beneficial relationship. India needs Tesla's expertise to manufacture electric vehicles and develop the domestic EV industry, while Tesla needs India because the country is the third-largest market in the world — and middle-class people in India are "really scouting for EVs, specifically in the luxury segment."

What's happening next week?

Interest rate decisions and inflation readings dominate the economic calendar next week. Indian IPOs are scarce as the end-of-the-year lull descends.

December 19: U.S. third-quarter GDP final figures, Bank of Japan interest rate decision, Bank of England interest rate decision

December 20: U.S. personal consumption expenditures price index for November, India monetary policy meeting minutes, Japan inflation rate for November, Euro zone consumer confidence flash data for December