Causes of inflation: demand-pull, cost-push, structural and expectations

Detail

0. The big picture: four families of causes

• Inflation is a steady rise in the general price level. It is measured in India mainly by CPI (Consumer Price Index), and also by WPI and the GDP deflator.
• Economists group its causes into four families:
• Demand side (demand-pull): buyers want more than the economy can produce.
• Supply side (cost-push): it costs more to produce goods, so sellers charge more.
• Structural: long-lasting bottlenecks in a developing economy keep some prices high.

• Expectations: people's beliefs about future prices push prices up today.

• In real life these causes mix. A monsoon failure (supply) can raise inflation expectations, and those expectations then feed wage demands.

• India's CPI now has a newer base. MoSPI has issued its first press release of CPI on base 2024 = 100 [7] (NCERT: base 2012 = 100).

1. Demand-pull inflation

1.1 Definition

• Demand-pull inflation happens when aggregate demand (total spending by households, firms, government and foreigners) is higher than the goods and services the economy can supply.
• Popular phrase: "too much money chasing too few goods."

1.2 The Class 12 view: excess demand and the inflationary gap

• Full-employment output: the output an economy produces when all its willing workers and machines are in use.
• Equilibrium output: the output at which aggregate demand = aggregate supply.
• Excess demand: aggregate demand at full-employment output is more than full-employment output.
• The shortfall is called the inflationary gap.

• Output cannot rise any further, because all resources are already in use. So the extra demand only pushes prices up in the long run.

• Deficient demand: aggregate demand at full-employment output is less than full-employment output.

• The shortfall is called the deflationary gap.

• It leads to falling prices and unemployment.

• Worked example:

• Full-employment output = ₹1,000 crore.
• Aggregate demand at that output = ₹1,100 crore.
• Inflationary gap = 1,100 − 1,000 = ₹100 crore.
• Real output cannot grow, so the extra ₹100 crore of spending shows up as higher prices, not more goods.

1.3 A typical route: deficit-financed spending

• Deficit financing: the government spends more than it earns and covers the gap by borrowing, or in the past by printing money.
• The chain:
• The government spends more, so incomes and demand rise.
• Output is already near full capacity and cannot expand.
• More demand meets a fixed supply, so prices rise.

1.4 Output gap: the RBI's working measure of demand pressure

• Formula: Output gap = Actual output − Potential output. It is often shown as a % of potential output.
• Potential output: the most an economy can produce over time without speeding up inflation (see growth-theories-business-cycles).
• Positive gap: the economy runs above capacity, which creates inflationary pressure.
• Negative gap: there is slack (unused capacity), so pressure on prices is low.
• Worked example:
• Actual GDP = ₹102 lakh crore; potential GDP = ₹100 lakh crore.
• Output gap = (102 − 100) / 100 × 100 = +2%, which signals demand-pull pressure.

• If actual GDP were ₹97 lakh crore, the gap would be −3%, which means slack and weak pressure on prices.

• Potential output cannot be observed directly. It is only estimated, so the output gap is an estimate too, and it gets revised often.

1.5 Money supply and prices (Class 11, Correlation, Example 2)

Price index (X)	120	150	190	220	230
Money supply, ₹ crore (Y)	1,800	2,000	2,500	2,700	3,000

• Step deviation method: subtract a chosen value from each number and divide by a common factor, so the arithmetic gets easier. The value of r does not change.
• U = (X − 100)/10 → 2, 5, 9, 12, 13

• V = (Y − 1700)/100 → 1, 3, 8, 10, 13

• Karl Pearson's formula: r = [nΣUV − (ΣU)(ΣV)] / √{[nΣU² − (ΣU)²][nΣV² − (ΣV)²]}

• n = 5; ΣU = 41; ΣV = 35; ΣU² = 423; ΣV² = 343; ΣUV = 378
• Numerator = 5×378 − 41×35 = 1,890 − 1,435 = 455
• Denominator = √[(2,115 − 1,681)(1,715 − 1,225)] = √(434 × 490) ≈ 461.2

• r ≈ 0.98, a very strong positive correlation. NCERT calls this "an important premise of monetary policy".

• Caution: correlation is not causation.

• Money may drive prices, which is the quantity theory view: MV = PT (see money-evolution-functions).
• Prices may drive money: when prices rise, people and firms need more money for transactions, so banks lend more.
• A third factor, such as fast GDP growth, may drive both.

2. Cost-push inflation (supply side)

2.1 Definition

• Cost-push inflation: production costs rise (wages, raw materials, energy), so aggregate supply shifts left.
• Result: prices rise and output falls at the same time.

• If this lasts, it is called stagflation (stagnation + inflation).

• Demand-pull vs cost-push:

• Under demand-pull, prices ↑ and output ↑ in the short run.
• Under cost-push, prices ↑ and output ↓.

2.2 Supply shocks

• Supply shock: a sudden change in the supply of a key input.
• Examples:
• Monsoon failure and heatwaves: less food output, so food prices rise.
• 1973 oil embargo: Arab oil producers cut supply, crude prices rose about four times, and stagflation followed across the world.

• 2022 Russia–Ukraine war: oil, gas, fertiliser, edible oil and wheat all became dearer.

• Recent Indian evidence: food inflation fell to 8.39% in December 2024 from 10.87% in October 2024, which shows how volatile supply-driven food prices can be [6].

• Headline CPI inflation, annual average: 6.69% (2022), 5.65% (2023), 4.95% (2024) [6].

2.3 Imported inflation

• Imported inflation: inflation that comes from abroad through the prices of imported goods.
• Main channels:
• Crude oil: India imported about 300 million metric tonnes of crude and petroleum products in 2024-25. Domestic producers supply only about 13% of oil, so import dependence is about 87% [5] (NCERT: "over 85%").
• Edible oils: India imports a large share of its needs.

• Rupee depreciation: the rupee loses value against the dollar, so every import becomes dearer in rupees.

• Worked example (rupee channel):

• Crude = $80 a barrel. At ₹75/$, one barrel costs ₹6,000.
• The rupee weakens to ₹83/$. The same barrel now costs ₹6,640.
• The rupee cost of oil rises 10.7%, even though the world oil price did not change.
• Dearer diesel raises freight costs, and freight costs then push up the prices of vegetables, cement and many other goods.

2.4 Wage-price spiral

• Wage-price spiral: a loop in which rising prices and rising wages keep feeding each other.
• Prices rise, so workers demand higher wages.
• Higher wages raise firms' costs.

• Firms raise prices again, and the cycle repeats.

• Example: prices rise 6%, so workers win an 8% wage rise. Labour costs rise, firms raise prices by another 5%, and workers then ask for more.

• Wages that are indexed (linked automatically to a price index) can speed up the spiral. Dearness Allowance, for example, is linked to CPI-IW (Consumer Price Index for Industrial Workers).

2.5 Greedflation (profit-led inflation)

• Greedflation: firms raise prices beyond the rise in their costs, which widens their profit margins.
• It happens mostly in concentrated markets (a few big sellers, weak competition).
• Example: input costs rise ₹5 on a ₹100 product, but the firm raises the price by ₹12. ₹7 of that is extra margin.
• Policy link: competition policy, through the Competition Commission of India, is a tool against inflation too.

3. Structural inflation

• Structural inflation: inflation caused by long-lasting supply bottlenecks that are typical of developing economies. It is not caused by short-term excess demand.
• Indian bottlenecks:
• Low farm productivity: low yields in pulses and oilseeds.
• Poor storage and cold chains: a lot of the harvest is wasted, so prices jump between harvests.
• Infrastructure gaps: poor roads, power and logistics raise costs.

• Market rigidities: limits under APMC (Agricultural Produce Market Committee) laws and long chains of middlemen, so the farmer's price and the consumer's price are far apart.

• The structuralist reading: food inflation in India stays high because of these supply problems.

• A key line: monetary tightening cannot grow more pulses.

• Raising the repo rate (the interest rate at which the RBI lends money to banks for a short time) cools demand, but it does not add supply.

• Remedy: supply-side reforms. These include irrigation, storage, crop diversification, market reform and buffer stocks.

4. Inflation expectations

4.1 Definition and the self-fulfilling loop

• Inflation expectations: what households, firms and markets believe future inflation will be.
• The RBI tracks them through its Inflation Expectations Survey of Households (IESH).
• The self-fulfilling loop:
• People expect high inflation.
• Workers bargain for higher wages, and firms raise prices early.
• Expected inflation becomes actual inflation.

4.2 Anchoring expectations: the Indian framework

• Anchoring: expectations stay stable around the official target, so a one-off shock does not turn into lasting inflation. Credible monetary policy makes this possible.
• Legal basis:
• The RBI Act, 1934 was amended in May 2016 to give flexible inflation targeting (FIT) a legal basis.

• On 5 August 2016, the Centre notified a target of 4% CPI inflation, with an upper limit of 6% and a lower limit of 2%, for the period up to 31 March 2021 [2].

• Reviews:

• First review (31 March 2021): the target and band were kept for 1 April 2021 – 31 March 2026 [3].
• The RBI issued a Discussion Paper on Review of the Monetary Policy Framework in August 2025. It asked, among other things, whether headline or core inflation should be targeted [3][4].

• Second review: a Gazette notification of 25 March 2026 reportedly kept 4% ± 2% for another five years, up to March 2031 [4]. Verify this against the Gazette text.

• Policy practice:

• The RBI acts early against shocks that may persist, such as a wage-price spiral or rising expectations.

• It may "look through" short vegetable-price spikes, because these reverse on their own and rate hikes cannot fix them (framework in banking-monetary-policy).

• Why 4% and not 0%: a little inflation gives room for relative prices to adjust. It also keeps a safety margin away from deflation.

5. Matching the cause to the remedy

Cause	Main driver	Best tool
Demand-pull	Excess demand, positive output gap	Monetary tightening (repo ↑), fiscal consolidation
Cost-push / supply shock	Input costs, oil, weather	Supply management: duty cuts, buffer stocks, imports
Imported	Crude, edible oil, rupee fall	Forex intervention, tax cuts on fuel, diversifying import sources
Structural	Farm, storage, market bottlenecks	Long-term reforms in agriculture and logistics
Expectations	Loss of credibility	Credible inflation targeting, clear communication

Prelims Hooks

• Inflationary gap = aggregate demand at full-employment output minus full-employment output. It raises prices, not real output.
• Output gap = Actual output − Potential output. A positive gap means inflationary pressure; a negative gap means slack.
• Cost-push inflation shifts aggregate supply left, so prices ↑ and output ↓. Demand-pull shifts aggregate demand right.
• NCERT's money supply–price index example gives r = 0.98. Correlation shows co-movement, not causation.
• A depreciating rupee causes imported inflation. India's oil import dependence is about 87% (2024-25) [5].
• The legal basis for FIT is the RBI Act, 1934, amended in 2016. The Central Government, in consultation with the RBI, sets the target, not the RBI alone [2].
• Target: 4% CPI (combined) ± 2%. The first notification covered Aug 2016 – Mar 2021, and the target was kept for 2021–26 [2][3].
• The Inflation Expectations Survey of Households is run by the RBI, not by MoSPI.
• Trap: the structuralist view says monetary policy cannot cure supply-driven food inflation.
• Greedflation means firms' margins grow beyond their cost rise. It is more likely in concentrated markets.

Mains Points

• Diagnosis before cure:
• Food inflation in India is mostly supply-driven and structural. For example, food inflation was 10.87% in October 2024 while headline inflation averaged 4.95% in 2024 [6].
• Using repo hikes against it hurts growth without adding supply.

• This supports the RBI's "look-through" approach to temporary shocks. It also shows why supply reforms matter: storage, cold chains, APMC reform and self-sufficiency in pulses and oilseeds.

• The headline vs core debate:

• The 2025 RBI Discussion Paper asked whether food should stay in the target [3][4].
• Keeping headline CPI: food is a large share of household budgets, and food prices shape inflation expectations.
• Moving to core: interest rates cannot fix monsoons, so targeting core inflation (excluding food and fuel) avoids needless tightening.

• The 2026 renewal of 4% ± 2% shows a preference for credibility and anchoring [4].

• External vulnerability:

• About 87% oil import dependence [5] plus rupee depreciation makes India prone to imported cost-push inflation.

• Energy security policy works as inflation policy: ethanol blending, renewables, strategic petroleum reserves and diversified crude sources all help.

• Fiscal–monetary coordination:

• Deficit-financed spending at full capacity creates demand-pull inflation.
• Fiscal discipline and FIT work together. Fiscal discipline stops the demand-pull route, and FIT keeps expectations anchored, so wage-price spirals do not take hold.