Guwahati/Agartala: Except Sikkim and Meghalaya, the six remaining northeastern states experienced deficit pre-monsoon rains due to lack of rain bearing clouds, water vapour and monsoon trough from the Bay of Bengal, experts and weather scientists said.
According to the Indian Meteorological Department (IMD), during the three-month long pre-monsoon period (March-May), Mizoram witnessed large rainfall deficiency of 67 per cent followed by Tripura (59 per cent), Nagaland (44 per cent), Assam (40 per cent), Manipur (37 per cent) and Arunachal Pradesh (27 per cent).
Sikkim experienced excess rainfall of 36 per cent during the pre-monsoon period, while Meghalaya though observed nine per cent shortage of rainfall, as per the IMD norms, it is categorised as normal.
IMD Tripura Director Dilip Saha said that the winds were not favourable for the expected pre-monsoon rainfall.
"We need southerly winds for rain. The northeastern region-centric rain producing weather conditions and rain bearing clouds did not develop adequately, causing deficient rainfall in the pre-monsoon period. However, we expect normal rainfall during the monsoon," Saha told IANS.
The northeastern region comprising Assam, Arunachal Pradesh, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim and Tripura normally witnesses normal or heavy rainfall during the four months of the southwest monsoon - June to September.
According to the IMD, the monsoon onset over Kerala is likely to take place on Thursday.
"If the southwest monsoon starts in Kerala on June 3, it would take another 5-6 days for it to arrive in the northeastern region," the senior IMD official said.
According to IMD records, Assam, which gets devastated badly by floods every year between June and September, recorded 327.6 mm rainfall during the pre-monsoon period (March-May) against the expected 543.6 mm.
According to the Assam State Disaster Management Authority (ASDMA), at least 122 people were killed in 22 districts in the devastating floods last year, while 26 others were killed in landslides.
Last year's floods affected around 60 lakh people in 5,378 villages in 30 of the state's 34 districts.
Agriculture experts said that at the moment there is no major threat to Kharif crops as irrigation facilities are more or less active in most parts of the northeastern region.
However, the Assam tea industry apprehends that the prolonged drought-like situation might cause a crop deficit from January to May this year, amounting to about 40 per cent, over the same period in 2019.
North Eastern Tea Association (NETA) adviser Bidyananda Barkakoty, citing a recent study, said that due to the protracted drought-like situation, the crop deficit from January to May this year would be about 60 million kg, compared to the same period in 2019.
"We have not compared crop figures with 2020 because last year the crop deficit from January to May was 78 million kg due to the Covid-induced lockdown. In percentage terms, the crop deficit from January to May this year would be about 40 per cent compared to the same period in 2019," Barkakoty said.
He said the average rainfall deficit is about 45 per cent from January to April this year compared to the same period last year in Assam's two main tea growing districts - Golaghat to Tinsukia.
He said that nowadays rainfall is highly localised and there is a difference in the quantum of rainfall within a few kilometres.
Assam, which roughly accounts for 55 per cent of India's total tea production of 1,389.70 million kg, has 856 large tea gardens and over a lakh small tea growers, engaging around 10 lakh workers in this industry.