The year will remain a watershed in the state's politics as Mamata became its first woman chief minister. Backed by the success of her agitation against land acquisition and riding on the slogan for change, the Trinamool Congress-Congress combine inflicted a crushing defeat on the Left Front with Trinamool alone bagging 185 seats in the 294-member Assembly.
Congress with 42 seats finished ahead of CPI-M which could barely manage to win 40 seats.
The new government signed the historic Gorkhaland Territorial Administration Accord on July 18, giving more autonomy to the hills and bringing much-needed peace to the Darjeeling Hills and the adjacent plains in North Bengal's Jalpaiguri district.
In its first six months, the government was dogged by a number of mishaps like the bridge collapse at Bijanbari in Darjeeling on October 22 that claimed 24 lives and the death of over 40 children at the B C Roy Paediatric Institute, the Burdwan Medical College and in Malda during September-October.
The worst-ever disaster of its kind in the state took place in the early morning of December 8 when a fire in the basement of the annexe-I building of AMRI Hospital in Dhakuria caused toxic smoke to engulf the building, resulting in the death of 93 patients.
A hooch tragedy in the state's South 24-Parganas district left nearly 130 people dead and many battling for life since the night of December 13-14.
While Banerjee earned accolades for visiting Sikkim with offers of help after the September 18 earthquake, the state police department, which she heads, came for criticism when it opened fire on a group which was opposing disconnection of illegally hooked electrical wires at Magrahat in South 24-Parganas on December 12.
After her swearing-in at the Raj Bhavan on May 20, Mamata chose to walk to the state secretariat Writers' Buildings, as tens of thousands of people lined up the streets, on balconies and even perched themselves precariously from parapets for a glimpse of the former Railway Minister.
Briefing newsmen after her first Cabinet meeting that very day, she said her immediate priorities were to return 400 acre from the Tata Motors factory at Singur to unwilling land donors, solve the problem in the Darjeeling Hills, work out a special package for 'junglemahal', uplift of minorities, review cases of political prisoners and restoring work culture among government employees.
She also announced that her ministers will henceforth attend office on Saturdays to speed up government business.
True to her promise, her government passed the Singur Land Rehabilitation and Development Bill, 2011, in less than a month of coming to power, paving the way for return of land to the unwilling land donors.
Her initiative, however, received a jolt when the Tatas challenged the litigation in the Calcutta High Court. A single bench of the court held the legislation to be constitutional, but the matter is now pending before a division bench of the high court on an appeal by Tata Motors.
In a bid to solve the Maoist menace in the 'junglemahal' areas, Banerjee nominated a group of interlocutors to open a dialogue with the ultras, but the Maoists set a month-long deadline from October 1 for the government to withdraw the joint forces, permit Maoist meetings and processions and release political prisoners as pre-conditions for the talks.
During her first visit as chief minister to junglemahal on October 15, Banerjee, however, gave the Maoists seven days to surrender arms or face a crackdown by the joint forces.
While warning the Maoists, she also announced a slew of projects for junglemahal, including a polytechnic institute, four colleges, an employment bank, drinking water projects, incentives for procuring tendu leaves and houses for over 5,000 villagers.
She also announced opening of new PDS outlets in junglemahal for providing essentials to BPL population and tribals at cheap prices.
Her anti-Maoist initiatives received boost when dreaded Maoist Jagori Baske and her husband Rajaram, also a member of a Maoist squad, surrendered before her on November 17.
Meanwhile, the killing of top Maoist leader Koteswar Rao alias Kisenji on November 24, has put negotiations with the ultras to a halt as the interlocutors declined to continue with the talks and quit.
If the Maoist problem remains a thorny issue with the new government, its biggest headache is perhaps the debt burden of Rs 2 lakh crore and the virtually-empty state coffers it inherited from the previous Left Front government.
After coming to power, Banerjee made several attempts in persuading the Centre to agree to a bailout package and the Union government agreed to a grant-in-aid of Rs 9,200 crore and an enhanced borrowing limits.
State Finance Minister Amit Mitra has also held meetings with his central counterpart Pranab Mukherjee on the issue, but the Centre was yet to announce a bailout package, saying that it cannot make an exce