Every time you pressure-cook a handful of toor dal, you are holding the product of a delicate biological process that heat is quietly destroying.
India is the world’s largest producer and consumer of toor dal, also called pigeon pea, growing over 4.5 million tonnes annually across Maharashtra, Karnataka, Madhya Pradesh and Andhra Pradesh.
Dal feeds over a billion Indians every single day. And it is under serious threat.
This is the latest story in Climate on My Plate, India Today Science’s new series on how the climate crisis is reshaping the everyday things you eat, drink, buy and own. This week, it is the savoury toor dal you crave.
WHY IS HEAT KILLING TOOR DAL BEFORE IT REACHES YOUR PLATE?
Toor dal is a warm-season crop, but it has strict temperature limits. It grows best between 26 and 30 degrees Celsius.
Once temperatures cross 32 degrees Celsius during the flowering stage, something irreversible happens inside the plant: pollen grains fail.
Pollen failure is not a metaphor, but a measurable biological event. When temperatures cross the threshold, pollen loses viability, which means it can no longer fertilise the flower.
The flower then drops from the plant entirely, a process scientists call floral abortion. No flower means no pod. No pod means no dal.
India’s average temperatures have already crossed that threshold across large parts of the toor-growing belt.
According to data from the India Meteorological Department (IMD), maximum temperatures during the kharif cropping season, from June to October, have risen by 0.6 degrees Celsius per decade since 1980.
WHAT HAPPENS INSIDE A TOOR DAL FLOWER WHEN IT IS TOO HOT?
The damage begins long before the flower falls. Heat stress disrupts pollen tube growth, the biological mechanism through which a pollen grain travels to fertilise the ovule inside the flower.
Without successful fertilisation, the plant has no reason to sustain the flower and sheds it.
A study published in the Journal of Experimental Botany found that exposure to temperatures above 33 degrees Celsius for even six hours during the flowering stage reduced pigeon pea pod set by up to 40 per cent.
The effect compounds. Toor dal is a long-duration crop. It flowers across several weeks, and if each spell of heat causes another round of floral abortion, the cumulative pod loss can devastate an entire harvest.
WHY ARE ERRATIC RAINS MAKING THINGS WORSE?
Heat is not the only problem. Toor dal needs moisture during pod development but cannot tolerate waterlogging during flowering.
Climate change is delivering both extremes at the wrong times.
The Council on Energy, Environment and Water documented that 55 per cent of India’s agricultural districts experienced a shift in rainfall patterns between 2013 and 2022, with intense downpours replacing steady rain.
When heavy rain arrives mid-flowering, it washes pollen off flowers before fertilisation can occur.
When the dry spell that follows is hotter than usual, the next flush of flowers aborts again.
Maharashtra, which produces roughly 35 per cent of India’s toor dal, has seen consecutive years of erratic monsoon behaviour aligned precisely with this pattern.
WHY DOES A FAILED POLLEN GRAIN COST YOU RS 200 A KG?
The answer is simple arithmetic. Fewer pods per plant means less dal per hectare.
Less dal per hectare means tighter supply. Tighter supply means higher prices.
Retail toor dal prices in India crossed Rs 200 per kg in late 2024, the highest in over a decade, according to data from the Department of Consumer Affairs.
The National Cooperative Exports Limited reported that domestic toor dal production fell short of demand by over 1 million tonnes in 2024, pushing India to import dal from Mozambique, Tanzania and Myanmar at premium prices.
That import cost gets passed down the supply chain directly to your kitchen.
The dal bowl on your table is not just a staple.
It is a receipt for everything climate change is doing to a single pollen grain in a field you will never visit.
#ClimateOnMyPlate
